Sync between two nodes #21266

I'm using the latest release of bitcoin (0.21.0) with private blockchain. I have two nodes running on localhost When I'm generating a new block by using generatetoaddress I receivedthis error:

error: Could not connect to the server 127.0.0.1:18001 (error code 0 - "timeout reached")

Make sure the bitcoind server is running and that you are connecting to the correct RPC port.

When I'm looking at the log, I see the same error as #12291:

Timeout downloading headers from peer=1, disconnecting

When I'm trying to mine a new block again, in some cases it's working and the block is created but not confirmed by the second node. The number of confirmations of the new block is 1.

In all cases the second node does not see new blocks.

EDIT: I checked the status of the rpc commands and it's still trying to create new blocks:

"active_commands": [
    {
      "method": "generatetoaddress",
      "duration": 7371995894
    },
    {
      "method": "getrpcinfo",
      "duration": 18
    }
  ]

What's your OS and configs?

Ubuntu 20.04.1 LTS

EDIT: I'm adding my bitcoin.conf files:

First file:

testnet=1

rpcauth=user:very_long_password
server=1

[main]

[test]
connect=127.0.0.1:17002
rpcconnect=127.0.0.1
port=17001
rpcallowip=127.0.0.1
rpcbind=127.0.0.1
rpcport=18001
listen=1
txindex=0
maxtxfee=0.02
wallet=node1

[regtest]

Second File:

testnet=1

rpcauth=user:very_long_password
server=1

[main]

[test]
connect=127.0.0.1:17001
rpcconnect=127.0.0.1
port=17002
rpcallowip=127.0.0.1
rpcbind=127.0.0.1
rpcport=18002
listen=1
txindex=0
maxtxfee=0.02
wallet=node2

[regtest]

Here is another insight, I tried to generate 10 blocks on my testnet, during the run time of the command I received the same error as above, but I didn't shutdown my nodes. After few hours I looked at it and indeed 10 blocks created but can see by only the node that generate them.

I recommend regtest for private chains, not testnet3.

Is this still an issue with a recent version of Bitcoin Core? If yes, what are the steps to reproduce?