Docker Covers not showing

Hi, I have openMediavault with Docker on armhf arch.
Installed calibre-web container and it is working. It loaded my library completely.

The problem is that the covers are not showing. I inspected it on browser and could see that the path is something like: /covers/BOOK_ID, but this /covers does not exist on container. I know it is related to the browser, but could not find elsewhere (unless it’s just a Alias).

There’s no option to Download Metadata.
The library is imported from Calibre I Library I have on y MacOS.

I could not find any clue on log files either.

Thanks

Update:
with user admin, there’s the option to edit the book (already updated to show to user).
So, I click there, select to fetch Metadata to update the cover. Calibre seems to freeze. The page starts to reload but it never finishes. Web interface seems to stop, any new tab on browser I open the web server does not respond and don’t return any page…
I need to restart container.