SocketException - Could not resolve host

Hi,
we are using Nakama with Unity and we have noticed some problems on our live production.
During player session we have randomly exception with sockets
Nakama.Ninja.WebSockets.WebSocketClientFactory+d__12.MoveNext
java.lang.Exception - SocketException : Could not resolve host ‘server.armedheist.com
So player can play game for 30 minutes and more and then he gets this error.
In attachment you can find image from firebase crashlytics.
Does anyone have a clue how to solve it? Any help is appreciated.

We are using:
Unity 2020.3.48f1
Nakama Unity 3.12.0
Server Framework Runtime language TS/JS