I have this problem. I have recently installed Jitsi on an Ubuntu following the instructions: jitsi devop quick start guide on github, jitsi secure domain devops guide, installing-the-token-plugin section on jitsi github.
There are some solutions in other threads as updating prosody config files but none of them worked for me.
/var/log/prosody/prosody.log ends with following two lines, which may be relevant:
Dec 10 07:02:42 bosha794d4c2-aaca-44e2-b474-5ca65c380ccf warn No available SASL mechanisms, verify that the configured authentication module is working
Dec 10 07:12:16 bosha794d4c2-aaca-44e2-b474-5ca65c380ccf info BOSH client disconnected: session close
Any piece of help will be appreciated