503 error on Invision Power Board

Hey all!

It's been a while since I've installed a brand new server, and I'm running into a weird issue.

On this new server, I have the following config:
CloudLinux plus PHP selector. I have the site set to PHP 7.2 through CL's tool.
Main website (WordPress) loads fine. Invision Power board (forum software) throws constant 503 error.

When I put the site back on Native PHP 7.2 taking it off of CL's PHP selector, IPB starts working. It's driving me crazy, I'm not sure what I'm missing.