What can we do better?

[GAW9576]

RobinK. That is what I did and it works fine.  I am trying to figure out why it happens in the first place as it seems widely variable to who and when it occurs.

I'd start with the broken SSL setup. If you alter the address from http://www.tost3.com/ to https://www.tost3.com/, the error will reproducibly occur. Any browser that defaults to https:// (someone mentioned the DuckDuckGo browser which, if memory serves, uses https everywhere) will run into trouble. Get rid of the unencrypted connection and you should be good to go. Me, I'll delete some cookies now to get back the CSS files...

Yep. I had to go and try adding the s after HTTP just to see for myself. It made everything weird again.
Of course I tried logging out and in again and it was still weird so I had to clear everything and log in again now everything is fine. I'm the one on Duck Duck Go. You may have already answered this and I didn't understand but Is there anything I can do to prevent the issue.