No messages visible in Talk

I recently upgraded to NC 13 and wanted to try the Talk app.
I started the app with 2 users in different browser sessions.
Problem is when I type a message in one window, it does not appear in the current window and also in the other user’s window, but also I don’t see any error in the Apache or nextcloud logs.
Is this a know issue?
If not, how to troubleshoot?