EADDRNOTAVAIL Exception In Dec, 2019 Update

[0x1100010010]

Server: heztner 256GB/1TB
OS: Ubuntu 16.04.6 LTS

An issue has appeared after the hard fork and pool update. monerod synced, monero-wallet-rpc up and running, lmdb synced without any exception, after starting pool.js, blockManager.js and worker.js started failing with the following exception.

PROMPT:
Upstream error from the block daemon. Resetting scanner due to: {"code":"EADDRNOTAVAIL","errno":"EADDRNOTAVAIL","syscall":"connect","address":"127.0.0.1","port":18081}

I have tried to fix the problem with prioritizing node and increasing outgoing connections with --add-priority-node=127.0.0.1:18081 --out-peers 500, but hasn't worked. Everything works fine without pool.js. I am still unable to identify the root cause.

Is it a problem in pool.js sessions or monerod config?
What are the possible solutions?
@Snipa22 @bobbieltd