[Solved] Error: Please check connection, Mattermost unreachable. If issue persists, ask administrator to check WebSocket port

Try Mikrotik as a router (and might be wifi device, there are many possibilities)
It is a really IT-swiss-knife ))))))

Ah, you mean the networking hardware - no interest in that because I am already established with Ubiquiti gear which works well. This discussion is about proxy servers and routing of subdomains.

Not pushing on anything, just saw your issue - tried to share what I know