I had the same problem with
- phone
- browser
- gallery
- calendar
(Messages and clock worked, others I did no try.)
I run journalctl -f as root and watched the log entries when starting the browser. firejail complained about /etc/hosts. Right, my /etc/hosts was a link to a file downloaded from https://github.com/StevenBlack/hosts
After restoring the original /etc/hosts file the problem is gone for the 4 affected applications.
P.S. It has already been reported that the browser does no longer obey such modified /etc/hosts files, I haven’t looked into the solution given there yet.