Sorry that didn’t pan out… Several other users have been reporting difficulty connecting to their Postgres databases suddenly, and the official status page is reporting “degraded performance” for at least one aspect of the .fly.dev domains, so this may be a widespread, transient metadata glitch:
https://community.fly.io/t/postgres-instance-refusing-connection-to-fly-app-flask/22297
https://community.fly.io/t/unable-to-reach-postgres-instance/22295
Edit: Three new ones that might also be broadly related, at least as far as plausibly being metadata discrepancies…
https://community.fly.io/t/machine-starts-and-stops-right-after/22307
https://community.fly.io/t/static-egress-ips-for-machines/22004/20
https://community.fly.io/t/machine-not-starting-automatically-when-receiving-requests/22308
Edit2: There’s a more specific, official status incident now…
https://status.flyio.net/incidents/ftd07gnytjl4
We are investigating increased proxy errors for apps communicating over Flycast internal networking
That’s a little different from the feature that you were trying, but it does involve closely related code, as I understand it. It’d probably be worth making another attempt once they’ve marked it fully over…