Hi,
I guess this might affect quite a few people so I hope I can save you a few
minutes to find the workaround:
Firefox 96.0 hangs after a while - loses connectivity
https://bugzilla.redhat.com/show_bug.cgi?id=2040189
upstream bug:
Infinite loop in HTTP3 hangs socket thread
https://bugzilla.mozilla.org/show_bug.cgi?id=1749908
Workarounds (from the upstream bug):
If anyone need to fix it, please open "about:config" in a
new tab.
Search : "network.http.http3.enabled"
change to false, then restart firefox.
Other workaround: Go to preferences -> Firefox Data Collection and
uncheck everything. Then restart Firefox
Felix