Gateway timeouts after error response

[freaktechnik]

Hi

I've discovered some very strange behavior with my nginx proxy manager: if a proxied service responds with an error (for example 403), the proxy manager will then respond with gateway timeouts for that service for a good while. From what I can tell the proxy no longer contacts the service during that time, leading me to think it must be something like a keep alive socket that's kept around for too long or similar. Having multiple endpoints for a proxy target (for example ipv4 and ipv6) mitigates the issue to some extent, since it will fall back to the other endpoint while it thinks it can't reach the first one.

I've tried all kinds of config permutations and custom nginx config options etc. but nothing has fixed it so far.