Read your own screenshot
If you want to simplify things, do this:
- Remove all the proxy mess in between the service and network
- Make sure it works properly, and you can address it by name
- Add proxy back and point to DNS to it
- Test again
Then just keep adding things back and find where it's breaking. I'm positive you have a hostname mismatch, or a messed up DNS record if you're using multiple proxies. Curl output would be helpful. Also check dig (hostname) to see what your DNS is responding with.