I'm running Gajim 1.4.6 (thank you to whomever just packaged this latest version) installed with Guix on a foreign distro (Debian bullseye).
Click on the "Start Voice Call" button on a contact which can receive calls. The interface box appears, saying "Calling...", then after a few seconds, says "Call ended" and then the box disappears. Calls worked okay on the previous major version of Gajim (1.3.x). Thank you for packaging 1.4.6 - it looks great! Joseph