A single user was no longer able to access his mailbox after a database failure due to a full log file partition. The problem only affected one user, while all other users were able to access the mailboxes in the database again. A general problem with the database could therefore be ruled out.
Auch die Einstellungen des Postfachs ließen sich im Exchange Admin Center problemlos aufrufen, erst wenn der Reiter „Postfachfunktionen“ ausgewählt wurde, trat eine Warnung auf:
Here is the text from the error message:
Warning
The mailbox /o=ORGNAME/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Configuration/cn=Servers/cn=SERVERNAME/cn=Microsoft System Attendant cannot be opened.
The server's event log then provided a crucial clue, as the mailbox in question was saved in the database from the error message:
Here is the text of the error message:
The performance counter ‚\SERVERNAME.MSExchangelS Store(DATABASENAME)\Quarantined
User Accessible Mailbox Count1 sustained a value of ‚1,00‘, for the ’10‘ minute(s) interval starting at ‚05.03.2021 13:42:00‘.
Threshold breached since ‚05.03.2021 12:12’. None Trigger Name:StoreQuarantinedMailboxCountTrigger. Instance:DATABASENAME
The error message states that at least one mailbox in the database is in quarantine. A quick check revealed that it was the mailbox of the user who could no longer access Exchange:
Get-MailboxStatistics ALIAS | ft *quaran*
Unfortunately, the quarantine function for mailboxes is not particularly well documented. In this case, the full log file partition probably caused the user's mailbox to be quarantined. However, this could no longer be traced exactly.
As can be seen in the screenshot, the quarantine function has a time limit. After 24 hours, a mailbox is automatically removed from quarantine. If you don't want to wait that long, you can use the following command to remove the mailbox from quarantine:
Disable-MailboxQuarantine ALIAS
The following command can be used to display all mailboxes that are in quarantine:
Get-Mailbox -Database DBNAME -ResultSize unlimited | Get-MailboxStatistics | Select DisplayName,IsQuarantined,QuarantineEnd | Where-Object {$_.IsQuarantined -eq $True}
If several mailboxes are in quarantine, the following command can be used to end the quarantine:
Get-Mailbox -Database DBNAME -ResultSize unlimited | Get-MailboxStatistics | Select DisplayName,IsQuarantined,QuarantineEnd | Where-Object {$_.IsQuarantined -eq $True} | Disable-MailboxQuarantine