Log into Self Service Portal in Sophos Central Email

Shared mailboxes do not have login credentials. According to the article from Microsoft there should be no login credentials for shared mailboxes https://learn.microsoft.com/en-us/microsoft-365/admin/email/about-shared-mailboxes?view=o365-worldwide. Messages sent to quarantine would appear in the administrative quarantine and can be released from there.

Yes. That's why I was wondering... The shared mailboxes appear as User Mailboxes. The spam reports aren't different and providing a link to the SSP. 

Activating the user object is of course possible but that's not the purpose of a shared mailbox. 

There should be an additional type called Shared Mailboxes besides Users, Distribution Groups and Public Folders, where spam reports do not mention any Self Service Portal, just present a relase or block button...

Guess I have to change my way of thinking... I added a new Email Policy with a group of all shared mailboxes and deactivated in this policy the "move to users quarantine" on any places