If you receive a "mailbox quota exceeded" message when trying to create a new mailbox when you believe you have sufficient quota to do so, it will normally be because you've deleted a user's mailbox, leaving active mobile devices associated to it.
The control panel will present the "mailbox quota exceeded" message because is still seeing mobile devices associated to an undeleted user, which in turn is telling the control panel that there's still some mailbox elements active against the user, meaning "technically", your mailbox quota is exceeded.
Follow these four simple steps each time you need to delete a mailbox and associated user to overcome this problem:
- Before deleting a user's mailbox, firstly click into the mailbox, then click the Mobile Devices tab
- Disassociate any mobile devices from the mailbox
- Now you can go ahead and safely delete the mailbox
- Finally, you will be able to successfully delete the user from the Users menu thus deleting all active associated mailbox elements.
