Tailscale in Plesk and QNAP run in Docker

Hello community,

I am new to Tailscale.

I want to connect my Plesk server to my QNAP so I can do a remote backup from Plesk to my NAS and also running Docker Swarm.
So I’m running tailscale in Docker on both servers.

I can ping both from my PC, but Plesk can’t ping QNAP and vice versa and can’t ping my PC.

Is there a configuration I’m overlooking?
I saw that all devices in tailscale have a different network. is this normal? like for Plesk: 100.120.9.10 and for QNAP: 100.123.123.100.

Cheers
Chris