Moved server to new location cannot change Subnet route

Ls,
I have a small problem.
I moved my Synology server to a different country and a new Ip range. Old was 192.168.0.0 new one is 192.168.178.0. On the same network there is existing Synology server acting as a exit node now with correct subnet rout (192.168.178.0). With this I could access all me stuff on both sites(servers, Modems etc). I want t0 switch off the old server because is will not be my primary server at this time. I wanted the new one as exit node. I can switch it on as exit node but the subnet rout is still 192.168.0.0.
Everything works normal in tailscale.

Actions I did so far: de-installed Tailscale rebooted the server and re-installed Tailscale. Removed the server from my account and added it again and renew authentication. But the Subnet route doesn’t change. Anybody a solution?
Thanks.