MS has recently released the Service Pack 2 for the Exchange Management Pack, and the same has been now temporarily removed from the Download Center due to the issue of mailbox quarantining when the free space availability on the Transaction Log Drive is low.
You may see the following entries on your event log, if you are affected with this issue.
Log Name: Application
Event ID: 10018
Task Category: General
The mailbox for user <guid>: /o=Contoso /ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=UserMailbox has been quarantined. Access to this mailbox will be restricted to administrative logons for the next 6 hours.
Log Name: Microsoft-Exchange-Troubleshooters/Operational
Source: Database Space
Event ID: 5410
The database space troubleshooter quarantined mailbox <guid> in database <DBName>.
To know more about this issue, read the below blog from Exchange Team.