Service unreachable only to some clients

Questions / Help
2

I can think of 2 things:

  1. HTTP/3. Do not enable it if you’re running multiple web-server instances on Fly. Fly’s UDP-proxy isn’t QUIC-aware: Regional/Node UDP ranges to alleviate IPv4 limits - #4 by ignoramous
  2. DualStack. Was the client using IPv6? Not sure if Fly has fixed all its IPv6 woes: Unable to access fly.io web and API over IPv6