502 Bad Gateway when internet is down

[starsoccer]

I have been running nginx proxy manager mostly without issue, but when I occasionally lose internet, nginx proxy manager which is running locally seems to for some reason lose connection to the proxied host even though its also local.

To give a simple example, I have nginx proxy manager running on a fixed ip of 192.168.0.100. I have a domain setup and configured with TLS. For this example I am going to just use the example domain of github.com.

So I have a service running locally on 192.168.0.101. The service listens on port 80, and I have nginx proxy manager proxying to this service but with https enabled. Nginx proxy manager is using a subdomain for this service which is service.github.com. Also in case its relevant, rather then have nginx proxy manager use the static ip(192.168.0.101) of the service, I have it using dns to resolve the service locally as I have my own DNS service running to.

So gist is nginx proxy manager is accepting requests to service.github.com and then looking up the local ip of service.internal and forwarding them. The problem is this breaks when I lose internet even though all services are running locally and I cant figure out why.

Anyways, the above setup works totally fine with no issues, until I lose internet at which point.