If you'd like to follow developments on this the Firefox bug seems to be this one : https://bugzilla.mozilla.org/show_bug.cgi?id=1749908
I'm confirming simply deactivating all Firefox telemetry is enough:
If you have changed the
network.http.http3.enabled setting as told above, you can reset it to it's initial value (
Restart Firefox to finish.
@tcit Not sure this is enougth as per https://bugzilla.mozilla.org/show_bug.cgi?id=1749908#c21 you can also trigger this issue with Google Cloud http/3 load balancer.
This is my personal Mastodon server, with a few extra people on it.