Revolt (Matrix Chat client) not working after upgrade to Trisquel 12 Ecne

I have just upgraded to Trisquel 12 Ecne using Software Updater. The upgrade went smoothly, just as it did when upgrading from 10 to 11.

All upgraded programs work without any issues, except for Revolt. The window appears, but it either gets stuck on "loading" or it shows nothing. From what I can tell the program is just a browser disguised as desktop application as it is tagged as "Safari on Linux" in the clients/devices section. It seems like the login to the server was successful, but some error is preventing the (HTML) elements from displaying. The GTK menu is still accessible though.

I've purged and reinstalled the program without success. From another device, I signed out the Revolt session, which brought me to the login screen. However, after logging in successfully it got stuck again on "loading"/showing nothing.

Any ideas how to fix this? I would try to delete the config folder but I couldn't find it in the usual places.