confusing SSL certificate error - is port number allowed?

I am getting an error accessing our site with iOS safari, and I managed to find the error using the remote debugger on safari, which seems to say the SSL certificate is wrong, but the error is pretty confusing: ``` [Error] Failed to load resource: The certificate for this server is invalid. You might be connecting to a server https://myserver.mydomain.com:36000/something that is pretending to be “myserver.mydomain.com” which could put your confidential information at risk. (connect, line 0) ``` Does anyone know what the issue might be? My best guess is the port on the url might be the problem, but as far as I know it should be valid. I don't get this error on any other browser I've tested, although there is an error on IE9 which I think might be the same problem, as it seems to be triggered when hitting the same url, but that has no useful information: ``` Error: Access is denied. undefined ``` (I don't get this error on IE9 with the "Access data sources across domains" option enabled, so it might not be related) Any clues how to debug this?