I wrote:
I'm available for anything that would help debugging this.
Looking further (in my case) it's related to apparmor,
kernel: audit: type=1400 audit(1770913688.152:456): apparmor="DENIED" operation="exec" class="file"
profile="/usr/bin/evince" name="/usr/bin/bwrap" pid=34166 comm="blocking-2" requested_mask="x"
denied_mask="x" fsuid=1000 ouid=0
Switching evince to complain mode (aa-complain /etc/apparmor.d/usr.bin.evince)
allowed it to start.
Shawn, maybe aa-complain /etc/apparmor.d/usr.bin.thunderbird would fix
it for you? (aa-complain is part of apparmor-utils).
Frederic
