Internet access Error / Proxmox / NGINX proxy manager

Hello there!
After around 2 hours I’ve been searching for a solution to this issue without any success.
I have installed Vaultwarden on a docker in Proxmox and assigned an domain with NGINX proxymanager which is in another container.
I can enter Vaultwarden over my domain and also over local ip.

The problem is the following… If I go to diagnostics, I can see, that the server says, that it has no internet connection. Therefore, I cant send any kind of invitations over SMTP.

Do somebody have any clue why this is happening? I must admit, that I’m not a pro in this field…

Its quite nice that nobody decided to help here…
I got the problem solved by just reinstalling the instance and restarting it before I proceeded to add my URL.