Hey @Feodor
Looks like you app has reached the configured concurrency limit.You should be able to see this message in the logs:
Instance <machine> reached hard limit of 25 concurrent connections. This usually indicates your app is not closing connections properly or is not closing them fast enough for the traffic levels it is handling. Scaling resources, number of instances or increasing your hard limit might help.
If you app can support more than 25 concurrent connections, you can set the correct limits as described here - Fly Launch configuration (fly.toml) · Fly Docs
Note that each active websocket connection (even when no data is transferred over it) counts towards the limit.
and I’m able to retrieve index.html page without any issues with the following command:
Yeah, this bypasses fly-proxy, so concurrency limits do not apply.