I’ve tried this, but it didn’t work. At home, I can access my cockpit server by typing the machines IP and port 8080. When I try this on the VPN though, it doesn’t work. I can access my routers settings, but not the server.
Can you post your config of the client? Remember to redact sensible information.

Here is my config file (I redacted the keys and changed up IP’s just to be safe):

[Interface] PrivateKey = [Redacted] Address = 192.135.163.201/24 DNS = 192.135.163.1 DNS = fritz.box [Peer] PublicKey = [Redacted] PresharedKey = [Redacted] AllowedIPs = 192.135.163.0/24,0.0.0.0/0 Endpoint = 9xs.myfritz.net:51609 PersistentKeepalive = 25

Two things:

192.135.163.0 is not a private IP… the private range would be 192.168.0.0/16. I guess that’s because you changed the IPs bit maybe better check that

And 0.0.0.0/0 means “all IPs” so it doesn’t really make sense to put the other one there.

Other than that I don’t see anything wrong…