Thanks, the issue has turned out to be custom startup code. I contacted support, and we're not sure why it is failing, but now have at least a temporary solution so that I can continue work. Temporary solution was to set SystemStart=0 in my cache.cpf file.
Thanks to Sean O'Connor for the simple solution, just ran chmod 777 /home/centos7 and my files and directories were accessible in Management Portal.
That was the solution! Thank you! I tried chmod 766, and that didn't work, it needs to be 777.
This is what ended up fixing the problem. I contacted support@intersystems.com on Pete Greskoff's advice, and they guided me through that process.
I actually can't even log in on the terminal. I have Caché installed on Linux, and when I run "sudo csession UppercaseCache" on the terminal, I get the following message:
How do I log on as a Privileged User?
I set it to minimal when I installed it, but accidentally (I'm a new to cache and all) removed the %All role from UnknownUser which was the user my log on defaulted to.