Error 500 - No Access
Using Jamroom
both.
As I understand it, the white page is caused by something in the jamroom system and its not really a 500 SERVER error.
The easiest recommendation from my end is: Use Jamroom Hosting, it works. ( you can create a server from here
https://www.jamroom.net/michaelcawood/hosting/create )
But if you'd like me to check out your server to see if there is anything that jumps out at me as to why its not successfully running jamroom, I can do that if you send me your login codes.
Not promising to fix your server, just going to have a quick look to see if its anything obvious. My first guess would be: corrupt template file thats not been uploaded properly, second guess would be: check and manually clear the caches, third guess would be to try another default skin.