Need help with Ports on Docker/Portainer


i’m beginning to learn Docker/Portainer/Bitwarden.

Today i installed Bitwarden as a Docker Container on my Raspberry.
At installation the container got the Port 9005 - this works for creating an account and login.

But when the container was stopped or restarted - it looses his port (in portainer overview there is no port visible) and the page isn’t reachable anymore.

What could be the reason for this problem?
Can anybody help me?

Thanks Andy