Perfex CRM xoauth2 not working after the update, outputing that the authorisation is unsuccesful, what may cause this?

Perfex recently introduced the ability to add office with the oauth2. I’ve followed the steps, added application where necessary, however, it authorize it properly, giving this –

SERVER -> CLIENT: 535 5.7.3 Authentication unsuccessful

All the settings from MS side seem to be fine to my knowledge. Is it perhaps some sort of cache issue?

I’ve tried tinkering with settings in MS, double checked if I took the wrong IDs and such, however, I am always still receiving this error