I'm talkin about an office365 shared mailbox, with my university enterprise subscription.
When I configure my personal account I found no issues
The problem is to configure the sMBX: if I try to it in imap mode, the process fails (probably because there's no way to set oauth2 parameter). Considering that a sMBX has no pwd, but you can access it using your pesonal account, I also tried to configure in Exchange mode: in the mail address field I put the sMBX address and then I choose auhomatic config. Whe I get redirected to my adfs authentication page I put my personal mail account and pwd....the result is that the account could not be added, because is already configured ('cause the system tried to add my pesronal account, not the sMBX one)