Talk federated conversation not working

Nextcloud version: 31.0.8
Talk Server version (eg, 14.0.2): 21.1.3
Custom Signaling server configured: yes 2.0.3
Custom TURN server configured: yes
Custom STUN server configured: no

In case the web version of Nextcloud Talk is involved:
Operating system (eg, Windows/Ubuntu/…): Windows 11, MacOS
Browser name and version (eg, Chrome v101): Edge 139, Opera 120

In case mobile Nextcloud Talk apps are involved:
Talk iOS version (eg, 14.0.2): yes
Talk Android version (eg, 14.0.2): 21.1.2

The issue you are facing:

I have 2 freshly installed instances of nextcloud with the same configuration on 2 different sites (2 different domains) that I joined to federation. Both servers are added as trusted for federation and federation of files and folders seems to work, but creating federated conversation ends up with unspecified error. The log on each side says something slightly different.

One side gets:

And the other one:

The same happens through mobile app.

In Talk settings the federation is allowed and HPB, STUN and TURN servers seem to be configured properly.

Is this the first time you’ve seen this error? (Y/N): Y

Steps to replicate it:

  1. Try to start create a federated conversation from either side.

I am using the linuxserver image, postgresql and caddy as reverse proxy.