We're using http proxy. Some users have access to a website and are allowed
to login on that website to place servicecalls.
When they try to access the login page, the URL is changed to an IP-address
followed by :100.
So this website is listening on non standard port 100.

I tried to set up an access rule for that port, but still get a 504 Gateway
timeout error.
How can I fix this issue?

Thank you.