I accidentally posted this question on an alt account but it disappeared and I can't find it.
I noticed yesterday on another laptop that when I click on Registration (not signed in on admin account), it directs me to a 404 Error page that says page is not found, within the WP theme template. This is a problem because it means that no one can register. I have a strong feeling that this is a wpForo issue and not a WP issue because it only affects the forum plugin and not the actual WP theme itself. Does that make sense?
How do I fix this? SOS send help and snacks.
1. Navigate to Dashboard > Forums > Settings > Members Tab, make sure the "Custom Authorization URLs" fields are empty.
2. Deactivate the plugins to make sure there is no plugin conflict. Deactivate the plugins one by one and check after each deactivation to find a problem maker.