Contacts app only shows spinning wheel but no content in webview

Hello, I just upgraded from owncloud 8.2.3 through the major releases to nextcloud 11.0.3
Unfortunately the contacts app is not working: contacts are not loaded, screen shows “spinning wheel”. I have no blanks in my user name.
Is there still a bug in the contact app? How can I make this work?
btw, the contacts are still accessible via dav (e.g. via mobile phone, or thunderbird).
Thanks for your help!

Hi @winnie_ld,

You should open a new topic here and only reference this one, because this here is solved already.
When you open a new topic, I suggest to attach possible error messages from the logs as well. Further more you could add the output of the browser console for Javascript, Network Analysis or Network runtime - wherever you see some messages/ output that might give a hint.