Networking via Zerotier/Tailscale stopped working on one of my systems, don't know what to fix here

Hello everyone,

hope this is the correct category for my problem.

Both Zerotier and Tailscale seemed to stop to function properly on one of my Linux boxes.
Said system has just been upgraded from Kubuntu 20.04 to 22.04.

I still receive the IP for their network and both of these also register the PC to be online when it is but I can no longer ping or access any other machine in my VPN network.

Already cleaned the DNS cache via resolvectl and checked for the correct nameservers being used (right now it’s my phone) but normally no dice.

I can use my phone to act as a proxy, this however seems a little inconvenient in the long run.

Do I miss something here?