Is your Google account a G Suite account? If it is, go online into your account settings and fix your mobile management settings for the box. If it's not a G Suite, have you tried logging into your account settings online and see if you see any issues under devices or with security settings?

Did you set up a restricted profile for parental controls or the like? That's the only thing I can think of that might apply.

How about following instructions on screen and not asking reddit?

Are you South African and you have Showmax installed?

Never got this one. Try searching for the error message online, I'm sure you'll find something about it.

Throw it in the garbage. MiBox sucks. I hate mine now. Was fine before the Android 9 update. PLEX is garbage now, and it's buggy as hell.