Need some help integrating with mybb

[Infernette]

So I've been struggling with integrating mybb in the new version (Of all the things...).
I've checked the config file for the mybb and took the info from there and put it into config_forums but when I make a test account I get "failed to create forum account". I know I haven't misspelled anything, because when I did I got a message that told me that access was denied for me to do that, so I don't know what is up.

I was trying to work on making my forums and site's inventories integrated and I don't know why it isn't working... (have to make the user id's match on both so I needed the auto sign-up)

I'm probably going to make myself a cup of noodles and try to fiddle around with this more to see what I can do to fix it on my own...