Hi @heinzpeda 

Thanks for posting in our business forum.

One by one.

So, is this a wired, wireless or wired and wireless issue?

Have you tried to replace the cables and see if there is any improvement?

Narrow down the issue, have you tried to use a single wired device to the router and to the switch individually to see if this is a problem on the router or switch?

Anything you find helpful after reading this guide can provide on the forum?

Hi @heinzpeda

heinzpeda wrote

I am not yet entirely sure what caused the issues, but until today I did not encounter them again. Either it was some Port Blocking in my switch, old routing tables in the switch, general bad luck, or weird tailscale subnet exposure configurations causing problems via my NAS and Raspberry Pi (although these devices were not really involved here). It seems to be working fine now

You probably should watch your Tailscale. How you set it up would affect your local network access as well. That's what I learned so far on a Linux-based server. It would simply affect my Internet access because of its settings.