Posting here to give the issue a bit more visibility, since it hasn’t yet seen Cloudflare devs on the original GitHub issue.
Tunnels using QUIC by default seem to drop connections and constantly reconnect (then fail, then reconnect, and so on) since just under a week ago for some users. See my personal logs (somewhat representative of others’ logs):
2022-05-02T19:40:34Z WRN Serve tunnel error error="connection with edge closed" connIndex=3 2022-05-02T19:40:34Z INF Retrying connection in up to 1s seconds connIndex=3 2022-05-02T19:40:34Z INF Changing protocol to quic connIndex=3 2022-05-02T19:40:35Z INF Connection b7e577ab-4a46-4003-a083-4de1cd730758 registered connIndex=3 location=IAD 2022-05-02T19:41:14Z INF Lost connection with the edge connIndex=1 2022-05-02T19:41:14Z WRN Serve tunnel error error="connection with edge closed" connIndex=1 2022-05-02T19:41:14Z INF Retrying connection in up to 1s seconds connIndex=1 2022-05-02T19:41:14Z INF Unregistered tunnel connection connIndex=1 2022-05-02T19:41:15Z INF Changing protocol to quic connIndex=1 2022-05-02T19:41:16Z INF Connection 65eb6307-114b-478a-ba5c-193607fb9068 registered connIndex=1 location=IAD
Issue started for me after rebooting my server, which triggered a new cloudflared instance. Issues did not exist prior to restarting. Issue persists on latest cloudflared version (2022.4.1).