Outlook Add Business Account without Licence

Hello,
I've got Outlook setup on my personal computer. I am logged in with a personal and a business Account, with an Office 365 License applied to both accounts. Also, some IMAP Accounts, but they shouldn't matter.

I recently got access to another business account which doesn't have a valid license for any desktop apps.
Adding the account via autoconfiguration failed, obviously (sadly). Even tho I have the right to use Outlook, so I naturally I want to be able to add all my mail accounts.

The second option I tried was adding the mail via the IMAP servers, provided by the settings in outlook.office.com.

Which only throws me the following errors:

• 8004DF00-0-0-560
• 8004DF00-0-0-430
• 8004DF00-0-0-733

Anyone got an idea or a solution to the problem?

Thanks in advance
Regards Lukas