I can't create my own library

Server Version#: 4.47.3
Player Version#: 4.47.3

I have installed PMS on Docker, on my own server in the internet. I access the domain, try to create a library and I get this horrendous message:

… What does it mean, download the Plex media server?! I’m already running the Plex Media Server!!!

How to add/claim my server? I have spent hours searching and haven’t found anything. The web interface is not intuitive.

scroll down to:

-e PLEX_CLAIM="<claimToken>" \

Supporting text:

PLEX_CLAIM The claim token for the server to obtain a real server token. If not provided, server will not be automatically logged in. If server is already logged in, this parameter is ignored. You can obtain a claim token to login your server to your plex account by visiting https://www.plex.tv/claim

I occur to the same issue.
It seems to be recognized as a client instead of a server.

Thanks, I logged out from all clients, restarted the server with a new PLEX_CLAIM and it worked, Plex was able to idenfity the server and I’m now able to add the library.