Calibre-Web Automated: uploaded books don't appear in the app

What app is this about, and its version: Calibre-Web Automated, 3.1m4-ynh2
What YunoHost version are you running: 12.1.35
What type of hardware are you using: Raspberry Pi 3, 4+

Describe your issue

I can upload books but they do not show in the app. I’ve not changed configs. I’ve reinstalled the app. I’ve uploaded PDFs and ePUBs and the behaviour is the same for both file types.

Share relevant logs or error messages

There are no errors in the app log. Here’s what the UI shows when I have uploaded a book:

Task: Upload: Upload done, processing, please wait…

Status: Finished

Progress: 100%

Run time: 0

Have you clicked on the Refresh Library button after uploading?

Good question! I actually did, no difference unfortunately.

Mmh it’s really strange. I’ve just installed a new test instance: it works.

So after installing, upload a book, then refresh, it should appaer. If not, please share logs