I have been experiencing ERR_CONNECTION_RESET error when i try to access my api from browser. But in curl it works properly.
I didn’t change any configuration from my fly.toml. I just update my certificate because i was deletade the app and create again, with same config and same name.
You may have since fixed this, but my guess would be the browser has a (now) invalid DNS cache. Since if you deleted the app and created a new one, I would assume Fly would assign it a new IP. The browser may have the old IP cached and so a connection to that could not be established.
You could rule that out by visiting (assuming Chrome) chrome://net-internals/#dns and clearing that particular host name.