I don't have a Dev install that I can test. I'd like to see if I do the same on a clean install if I get a grey screen.
One thing I remember about the last time I tried using external site loading was that Gmod didn't like dynamic pages. (That was years ago though)
For instance, you have some fancy CSS or something with that rotating logo at the top of your page.
Are you absolutely certain you had that before going HTTPS?
Also, I know it's not a direct to the rules page, but have you tried just setting your motd to "
https://neotekgaming.com/" ?
I'd be curious if even that worked.
When I tried using the full url in the link to that SSL checker page, even the SSL check mangled the url to "
http://neotekgaming.com/showthread.php?tid=4"
Either way, to anyone else monitoring this thread, does anyone else here on the forums have a test box they can test to see if they use "
https://neotekgaming.com/showthread.php?tid=4&pid=4#pid4" as motd URL if they too get a grey screen?
(It can't be a listen server, you'd likely not see motd)
I'm reasonably sure this isn't going to be a ULX issue, but more of a Gmod doesn't like some html/https issue.