MultiChain Developer Q&A - Recent questions tagged connection

Unable to connect second node to seed node – “Couldn’t connect to the seed node on port 4419”

Sun, 26 Oct 2025 06:59:49 +0000

Hi,

I’m currently setting up a MultiChain network (version 2.3.3 – protocol 20013) and facing an issue while connecting a secondary node to the seed node.

When I run the following command on the secondary node:

multichaind [chain-name]@[seed-node-ip]:[port-number] -datadir="E:\Multichain\nodes\SecondNode" -daemon

I receive this error:

Retrieving blockchain parameters from the seed node [seed-node-ip]:[port-number] ... Error: Couldn't connect to the seed node [seed-node-ip] on port [port-number] - please check multichaind is running at that address and that your firewall settings allow incoming connections.

Here are my setup details for context:

MultiChain version: 2.3.3 (Community Edition, protocol 20013)
Seed node IP: [seed-node-ip]
Port configuration: default-network-port = [port-number], default-rpc-port = [rpc-port]
OS: Windows Server on both nodes
Telnet test: Successful on port [port-number]
multichain.conf on seed node:
```
 
```
rpcbind=0.0.0.0 rpcallowip=0.0.0.0/0
Firewall: Port [port-number] opened for inbound/outbound TCP

Despite these settings, the secondary node still cannot connect.

Could you please help me identify what might be causing this connection failure?
Do I need to modify any additional parameters (such as bind, externalip, or interface configurations) for Windows environments?

Thank you in advance for your assistance.

Error while Establishing Connection: Multichain Node

Fri, 18 Aug 2023 09:00:24 +0000

Hello

I'm encountering an unexpected issue while attempting to establish a connection to a Multichain node. Despite following the recommended steps from the documentation, I keep encountering the following error message:

Error: Unable to connect to node: Connection refused

Here's a brief overview of my setup:

Multichain Version: 2.0.3
Operating System:Ubuntu Linux 20.04
Steps Taken:
- Installed Multichain using [Installation Method]
- Created a new chain named "[Chain Name]"
- Launched the node using the command: multichaind [Chain Name] -daemon

My Multichain configuration file ([config-file.conf]) appears to be correctly set up with the necessary parameters. I've also ensured that any firewall or network restrictions are not causing this issue.

Could someone please provide guidance on how to troubleshoot and resolve this connection error? Are there any specific log files I should examine for more detailed error messages? I'm eager to continue exploring the capabilities of Multichain, and any assistance would be greatly appreciated.

Thank you in advance for your time and expertise!

AWS Cloud9: Multichain Error: Couldn't connect to the seed node (Please help)

Mon, 25 Apr 2022 15:37:27 +0000

I am using AWS - cloud9 virtual machines for creation a multichain blockchain instance.

Unable to connect two virtual machine.
Error: Couldn't connect to the seed node 172.31.77.199 on port 4351 - please check multichaind is running at that address and that your firewall settings allow incoming connections.

Can't type the grant command on the first server.

Thu, 22 Apr 2021 03:09:21 +0000

I cant type the "multichain-cli chain1 grant connect" command on the first server. it says listening for API request on port ____. I need help

Error: multichaind: pthread_create.c:430: start_thread: Assertion `freesize < pd->stackblock_size' failed.

Mon, 20 May 2019 18:04:54 +0000

I am going through the tutorial and running the first set of commands. First server is Ubuntu 18.04, second sever is Mint 18.

After running all commands successfully including section 3, I shutdown both servers according to this answer because I wanted to start from scratch.

Now, whenever I repeat the process, I stumble in section 2. Specifically, when I issue:

multichaind chain1@[ipaddress]:[port]

from the second server, I get the error:

Retrieving blockchain parameters from the seed node [<ipaddr>]:[<port>] ...

multichaind: pthread_create.c:430: start_thread: Assertion `freesize < pd->stackblock_size' failed.

And cannot get past this.

Any ideas?

The peer connection was lost.

Wed, 08 May 2019 08:29:13 +0000

hello,

i connect to 3 node and operated.

but One node is disconnected.

How can I reconnect the node again?

"error: couldn't connect to server" when blockchain was created

Mon, 15 Apr 2019 12:06:28 +0000

I create the blockchain with:

multichain-util create test-db \
-default-network-port=4000 \
-default-rpc-port=4001

Then I start the node with:

multichaind test-db -rpcallowip=0.0.0.0/0 -autosubscribe=streams -daemon

And I get the proper output, stating that the node has been started successfully and is ready. And when I want to make calls against the API, f.e.:

multichain-cli test-db getinfo

multichain-cli test-db -port=4000 -rpcport=4001 getinfo

I get "error: couldn't connect to server"

The node is not getting connected Multichain

Mon, 17 Dec 2018 18:01:23 +0000

Hi,

while connecting to the second node, it is not moving further.I am a newbie to multichain

Retrieving blockchain parameters from the seed node 172.31.21.32:9743 ...

Other nodes can connect to this node using:

multichaind chain1@172.31.21.41:9743

Listening for API requests on port 9742 (local only - see rpcallowip setting)

Node ready.

Please help

Couldn't Connect to Seed Node

Wed, 26 Sep 2018 15:14:17 +0000

I have set up multichain on two Windows 7 VMs.

I successfully multichaind the chain on one VM, but when I try to connect to it from the second VM, I get a an error.

'Error: couldn't connect to the seed node 10.0.2.15 on port 7405 - please check multichaind is running at that address and that your firewall settings allow incoming connections.

I know that my host VM is running, and that the address is correct. I've tried connecting with the firewalls for both VMs off, but I still get the same error.

error: could not connect to the server

Sat, 26 May 2018 09:37:36 +0000

When I tried granting an address permission to connect to the blockchain. it shows error : could not connect to server. Why is it so?

couldnt connect to seed node, firewall problem

Fri, 18 May 2018 07:46:25 +0000

i followed this

https://blog.cotten.io/deploying-a-blockchain-with-multichain-on-amazon-ec2-b288ae118b30

& then

https://www.multichain.com/getting-started/

[ec2-user@ip-172-31-18-195 ~]$ nano ~/.multichain/alertchain-core/params.dat
[ec2-user@ip-172-31-18-195 ~]$ multichaind chain1@172.31.31.111:4287

MultiChain 1.0.4 Daemon (latest protocol 10010)

Retrieving blockchain parameters from the seed node 172.31.31.111:4287 ...
Error: Couldn't connect to the seed node 172.31.31.111 on port 4287 - please check multichaind is running at that address and that your firewall settings allow incoming connections.

What makes "connections" count result different when I called "getinfo" API?

Wed, 04 Apr 2018 03:37:06 +0000

We're running several multichain test node.

When I tried to call the API "getinfo" to query total peer count to show the result at "multichain explorer",

but each node shows different result.

Could you explain me what make the result different?

And I want to know how to get total peer count using "multichain-cli {mychainname} getinfo", or "getpeerinfo" or else.

Thank you in advance.

What happens if network connection to other nodes goes down?

Tue, 27 Mar 2018 14:33:09 +0000

What happens to a message if the network connection between this node and other nodes goes down? Does the mutichain server report an error, or does it hold onto the message until the connection is restored? Other nodes may continue to generate messages, perform mining and add to the chain, which means that when the connection comes up again the blockchain at my node is out of step with that used by the other nodes. Does the blockchain get synchronised before my message is added to the end, or is my message lost?

Can an asset being connected with one or more streams

Fri, 02 Mar 2018 10:20:50 +0000

Hello,

is an connection between assets and streams possible? In my case i want to change ownership of things. During this time, there severel parties which send different stuff to this "thing". When the thing is bought by an other user i want to transfer the thing with all data was safed.

As my understanding i can only change ownership of assets, streams are more or likely an immutable database.

Best Regards,

Upgrade 1.4.0 - Node wallet address not showing when attempting connection

Tue, 27 Feb 2018 07:47:51 +0000

After entering this command on 2nd node "multichaind chain1@ip_number:port" ...the created node address is not showing. Where can i find it so I can enter it into the 1st node?

Error: Couldn't connect to the server

Tue, 23 Jan 2018 06:36:46 +0000

Hi,

I am building multichain from the source code but when I run multichain-cli after creating the node, it throws me "Error: Couldn't connect to the server". I added the RPC port in multichain.conf and restarted the multichaind but still I get the same error. Could you please help?

The underlying connection was closed: The connection was closed unexpectedly.

Fri, 12 Jan 2018 16:42:22 +0000

I have a 2-node setup running. I'm able to issue commands successful from the command line. However, I can't get the same commands to work via C# code.

I'm getting the following error when calling any method:
"The underlying connection was closed: The connection was closed unexpectedly."

I'm using the following C# code

string method = "getinfo";
string chainName = "chain1";
string chainKey = null;
int id = 0;
string serviceUrl = http://192.168.133.185:4265/;
string Username = "multichainrpc";
string Password = "HFfnnSbMqSWtF7gb5wZUJZYwGcQ3p4BqkD72s2AYAB2q";

var ps = new JsonRpcRequest()
{
Method = method,
Params = args,
ChainName = chainName,
ChainKey = chainKey,
Id = id
};

var jsonOut = JsonConvert.SerializeObject(ps.Values);
var url = serviceUrl;
var request = WebRequest.CreateHttp(url);
request.Credentials = new NetworkCredential(Username, Password);
request.Method = "POST";
var bs = Encoding.UTF8.GetBytes(jsonOut);

WebResponse response = request.GetResponse();

Error: Unable to bind to 0.0.0.0:4373 on this computer.

Sat, 28 Oct 2017 21:50:16 +0000

I had to reboot main node of my multichain that's been running fine for many months. There were 20 nodes connected. After reboot I did the normal to fire up the chain again:

nohup multichaind chain1 -daemon &

But I now get the following error:

MultiChain 1.0 Daemon (protocol 10008)

MultiChain server starting

Error: Unable to bind to 0.0.0.0:4373 on this computer. MultiChain Core is probably already running.

Error: Failed to listen on any port. Use -listen=0 if you want this.

---

However, node 2 can connect fine and use API commands in interactive mode just fine. Node 1 is centralized API for our external systems so our block explorer, etc are not working now.

Node 2 and subsequent nodes connect just fine. Just node 1 is having the error.

I can go into interactive mode on node 1 as well but then I get errors:

$ multichain-cli chain1

MultiChain 1.0 RPC client

Interactive mode

chain1: getinfo
error: couldn't connect to server

I tried rebooting node 1 several times but same issue persists. I can restart the chain from node 2 but node 1 just won't connect. What's going on?

How to get the root node address to initialize the MultichainConnection rootnode property C#?

Thu, 21 Sep 2017 11:48:53 +0000

Getting an error "underlying connection was closed"

Thu, 21 Sep 2017 11:46:11 +0000

Error: Couldn't connect to the seed node 172.16.16.83 on port 2787

Tue, 19 Sep 2017 17:03:31 +0000

Hi Multichain,

I am getting the same problem again and again although I tried all solutions provided in previous questions. I am having no problem running and connecting two nodes on same computer(In different directories and on different ports) but on running two nodes on different computer is giving a error message. Please tell me where can I send debug.log file so that you can resolve my problem.

Thanks and Regards

Tarun

Couldn't connect to the seed node error on Ubuntu AWS EC2

Sat, 26 Aug 2017 19:06:00 +0000

I have our chain running for a few weeks now with 4 nodes. I can fire up new nodes on my AWS account and be connected and running in a few minutes. I can do this repeatedly with zero issues. I've launched, connected and mined with hundreds of testing nodes by now.

However, when ANY other server outside my AWS account tries to connect to our chain they get the same problem here:

https://www.multichain.com/qa/3381/couldnt-connect-to-the-seed-node-error-on-ubuntu-aws-ec2

I ran multichaind -debug=mchn -debug=mchnminor -debug=net on our chain but I don't see anything in the debug.log file at the timestamp when I try to connect.

Here's all I see around that time stamp on the debug.log

2017-08-26 19:03:42 (8 bytes) peer=1
2017-08-26 19:03:42 mchn: RECV: pong, peer=1
2017-08-26 19:03:42 received: pong (8 bytes) peer=1
2017-08-26 19:03:43 mchn: RECV: ping, peer=2
2017-08-26 19:03:43 received: ping (8 bytes) peer=2
2017-08-26 19:03:43 sending: pong mchn: SEND: pong
2017-08-26 19:03:43 (8 bytes) peer=2
2017-08-26 19:03:43 sending: ping mchn: SEND: ping
2017-08-26 19:03:43 (8 bytes) peer=2
2017-08-26 19:03:43 mchn: RECV: pong, peer=2
2017-08-26 19:03:43 received: pong (8 bytes) peer=2
2017-08-26 19:03:44 mchn: RECV: ping, peer=3
2017-08-26 19:03:44 received: ping (8 bytes) peer=3
2017-08-26 19:03:44 sending: pong mchn: SEND: pong
2017-08-26 19:03:44 (8 bytes) peer=3
2017-08-26 19:03:44 sending: ping mchn: SEND: ping
2017-08-26 19:03:44 (8 bytes) peer=3
2017-08-26 19:03:44 mchn: RECV: pong, peer=3
2017-08-26 19:03:44 received: pong (8 bytes) peer=3
2017-08-26 19:03:52 mchn: RECV: ping, peer=1
2017-08-26 19:03:52 received: ping (8 bytes) peer=1
2017-08-26 19:03:52 sending: pong mchn: SEND: pong
2017-08-26 19:03:52 (8 bytes) peer=1
2017-08-26 19:03:52 sending: ping mchn: SEND: ping
2017-08-26 19:03:52 (8 bytes) peer=1
2017-08-26 19:03:52 mchn: RECV: pong, peer=1
2017-08-26 19:03:52 received: pong (8 bytes) peer=1
2017-08-26 19:03:53 mchn: RECV: ping, peer=2
2017-08-26 19:03:53 received: ping (8 bytes) peer=2
2017-08-26 19:03:53 sending: pong mchn: SEND: pong
2017-08-26 19:03:53 (8 bytes) peer=2
2017-08-26 19:03:53 sending: ping mchn: SEND: ping
2017-08-26 19:03:53 (8 bytes) peer=2

Could this be something simple I'm using in security settings on AWS? I can connect nodes from inside my own AWS account but no one else can connect. All get the same error. The ports are wide open too.

Ideas?

Python Savoir connection error.

Fri, 28 Apr 2017 02:35:16 +0000

Hi i installed Multichain & Savoir in two nodes(two laptops) and started "chain1" from the node1 and node2 connected to the chain1. now i am trying to run the program(using Savoir) to connect to chain1 from node2 i am getting the following error in node2

requests.exceptions.ConnectionError: HTTPConnectionPool(host='localhost', port=4372): Max retries exceeded with url: / (Caused by NewConnectionError('<requests.packages.urllib3.connection.HTTPConnection object at 0x7f44a3d24e10>: Failed to establish a new connection: [Errno 111] Connection refused',))

node1 multichain.conf

rpcuser=multichainrpc
rpcpassword=vTxv7DnYxX1hx9ZH8uHepHHMaCf1c9ftGmtGYVcF4rN

node2 multichain.conf

rpcuser=multichainrpc
rpcpassword=EEhoZ4nE5czYwWtNQzUixNwtwmnhjjjChudMZSrMFAsB

node1 program

import Savoir
rpcuser='multichainrpc'
rpcpasswd='vTxv7DnYxX1hx9ZH8uHepHHMaCf1c9ftGmtGYVcF4rN'
rpchost = 'localhost'
rpcport = '4372'
chainname = 'chain1'
api = Savoir.Savoir(rpcuser, rpcpasswd, rpchost, rpcport, chainname)
print api
print api.getaddressesbyaccount("")[0] # working

node2 program

import Savoir
rpcuser='multichainrpc'
rpcpasswd='EEhoZ4nE5czYwWtNQzUixNwtwmnhjjjChudMZSrMFAsB'
rpchost = 'localhost'
rpcport = '4372'
chainname = 'chain1'
api = Savoir.Savoir(rpcuser, rpcpasswd, rpchost, rpcport, chainname)
print api
print api.getaddressesbyaccount("")[0] # working

Please can someone suggest me what i am missing here, do i need to add anything in the multichain.conf file in the node1.

Note : I have followed the same procedure 3 months back i was successfull that time.

python api connection (newbie)

Wed, 12 Apr 2017 03:34:39 +0000

Hello, Im new to this blockchain. I have setup the multichain and everything run as expected but when I tried to make rpc request using savoir it raised the exception. I know that's the problem with the connection that multichain server refused the connection. The question is, what is the step for savoir connection to the multichain server.. I mean the proper step and the config i need to put into the multichain.conf file... Sorry Im really new to this multichain.

connection count displays wrong number

Mon, 10 Apr 2017 10:25:54 +0000

I got 2 nodes each with different datadir, port, and rpcport. Since these 2 nodes are connected with each other, I thought the connection count for each node would be 1. However, 'getinfo' call displays 'connections : 3' instead of 1. What exactly does this 'connections' count mean?

RPC failed [Errno socket error] [Errno -3] Temporary failure in name resolution

Wed, 18 Jan 2017 19:18:39 +0000

Getting this error when trying to watch the contents of the blockchain by using the multichain-explorer

Data exchange between two private blockchains

Thu, 12 Jan 2017 10:22:03 +0000

I have two private blockchains from different users/systems within multichain. Now I will transfer data between the systems. System 1 asks for specific information from System 2 and System 2 will provide the required data. I thought that I could use streams for this scenario. But if the streams stored within the blockchain how I could transfer the data to another blockchain within multichain? My question in another way: How can I transfer data between two chains?

Automating Multichain command

Tue, 03 Jan 2017 11:27:53 +0000

This might be a bit out of the scope but I'm trying to run the multi chain instances on the same server and in doing so I'm trying to automate the tasks to get it started. However I am having a hard time getting anywhere with it. Would you be able to provide some insight into it?

ip=$(multichaind decibel -shortoutput=1 -miningrequirespeers=0 -discover -rpcuser=admin -rpcpassword=admin -daemon=1)

mkdir .multichain1

echo "ip address $ip"

addr=$(multichaind $ip -datadir=.multichain1)

echo "wallet $addr"

multichain-cli decibel -rpcuser=admin -rpcpassword=admin grant $addr connect,send,recieve

multichaind $ip -datadir=.multichain1 -daemon=1

The first task seems to block the other processes from being executed. Would it be possible to kill then restart later without having to reset anything?

A connection attempt failed because the connected party did not properly respond

Tue, 08 Nov 2016 04:49:22 +0000

Hello I have installed the multichain in a linux machine and created one chain. But when we are trying to access that chain by using C# wrapper for the MultiChain JSON-RPC API by PBJ Cloud through a window machine by using visual studio I'm getting error.

Error : {"A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 10.94.30.54:4335"}

Please help me.

Connection Error

Thu, 22 Sep 2016 13:53:25 +0000

I am using a windows 10 desktop in which i have created two ubuntu VM's which i am accessing through putty.

when i try to connect to chain from different node , it is not connecting and :

Error: Couldn't connect to the seed node 10.0.2.15 on port 7215 - please check multichaind is running at that address and that your firewall settings allow incoming connections.

when i test the ip with telnet it shows:

vagrant@precise64:~$ telnet 10.0.2.15 7215
Trying 10.0.2.15...
Connected to 10.0.2.15.
Escape character is '^]'.

when both my VMs are on the same system , do you think firewall is going to have any effect.

Any ideas , suggestions please

MultiChain-Explorer: Connection Error (ERR_CONNECTION_RESET)

Mon, 22 Aug 2016 06:51:45 +0000

Hi,

Having a bit of trouble connecting to the MultiChain Explorer. I installed and ran the explorer one day previous - everything worked fine. The explorer connected to my chain and displayed the correct information. However I cannot seem to connect today, even after restarting the explorer.

Chrome's output:This site can't be reached, The connection was reset. (ERR_CONNECTION_RESET). Hosted on Digital Ocean (Ubuntu 16.04.1x64). Multichain version alpha-23.

Input is appreciated, thanks.

RPC failed: [Errno socket error] [Errno 111] Connection refused catch_up_rpc: abort

Thu, 04 Aug 2016 12:47:29 +0000

Hi There,

I have followed the below link for setting up MultiChain Explorer:

https://github.com/MultiChain/multichain-explorer

We have successfully set-up MultiChain explorer on our Linux server. Done the necessary configuration in the "MultiChain.conf" file. We have also performed the necessary steps for launching the block-chain data into the explorer, but we are facing the below issue once we hit it from the browser:

RPC failed: [Errno socket error] [Errno 111] Connection refused

catch_up_rpc: abort

Below is the URL of our MultiChain Explorer set-up on our server:

http://serverIP:2750

Please, suggest us what could have gone wrong from our side. Any suggestion would be of great help.

Let me know if you need further details on the same.

Thanks & Regards,

Lipi Bhatt

Help! Connection to Mutlichain using Java Client?

Tue, 02 Aug 2016 08:05:18 +0000

How am I able to connect to Multichain block running on another server using a Java client? Thanks for the help

bitcoinj to MultiChain bitcoin - connection timeout

Thu, 26 May 2016 05:20:52 +0000

Hi, I cloned a copy of the modified BitcoinJ from: https://github.com/MultiChain/sample-bitcoinj.git and followed exactly all the instructions in the README file, including using the sample params.dat file provided (multichain_bitcoin.params.dat) without any modification ( so, I am running Multichain as a bitcoin network without assets and permissions).

However, I keep getting the following error messages -- it connected but timed-out after 5 seconds. Appreciate your kind advice. I have seen someone asking this before but there was no concrete answer.

Thank you very much.

Regards,

Ying

===========
13:01:34 21 PeerGroup.connectTo: Attempting connection to [128.199.223.47]:8333 (0 connected, 1 pending, 1 max)
13:01:34 22 NioClientManager.handleKey: Successfully connected to /128.199.223.47:8333
13:01:34 22 Peer.connectionOpened: Announcing to /128.199.223.47:8333 as: /bitcoinj:0.14-SNAPSHOT/WalletTemplate:1.0/
13:01:39 23 PeerSocketHandler.timeoutOccurred: [128.199.223.47]:8333: Timed out
13:01:39 23 PeerGroup.handlePeerDeath: [128.199.223.47]:8333: Peer died (0 connected, 0 pending, 1 max)

===========