I have been researching this error for several days now and I see that it comes up a lot with Outlook.com users but my scenario is different. I have one user only out of 25 total getting this error in Outlook (Home & Business 2016 installation) when connecting to our Exchange Server 2013 Standard Version 15.0 (Build 847.32) - this is the on-premises version NOT online. The computer getting the error is not joined to our domain as they are an off-site user. The full error is as follows:
Your mailbox has reached its maximum size limit at which you cannot send or receive any more content. Empty your deleted items folder from Outlook or delete messages from your mailbox to create more space.
File: \outlook\pstprx\storeas\utils\airsyncstatuscodes.h
Line: 104
HTTP/1.1 200 OK
MailStatus: 115
To re-try press F9...
0x80004005
The user can actually send and receive just fine as I've had them send several test messages which were successfully sent and received. However, the error keeps coming up with annoying frequency when the user has Outlook open. Deleting messages and emptying Deleted Items as the error suggests had no effect. I know that the OST file is well under any limits as I've checked both the actual file size on the computer and the size reported by Exchange Management Shell.
DisplayName TotalItemSize ItemCount
----------- -------------
---------
L 238.6 MB (250,143,914 bytes) 535
Most of the other users that have mailboxes on the Exchange server are using Outlook from Office 2013 to connect and I'm starting to wonder if this issue is due to this user being on Office 2016 version. When the user logs in with OWA there are no error messages.
Other things I've tried that have not solved the problem:
- Increasing the default mailbox size in Exchange from 2 GB to 100 GB
- Move user's mail to a PST file and deleting the account, deleting the OST and re-creating the account
- Restart mail server
Afaik the user does not send large amounts of bulk messages but does sent out sales-related e-mails that have brochures attached, I noticed about 4 of these that were stuck in the Outgoing folder. The attachment was about 8 MB in size. I deleted these but it had no effect on the frequency of the error message appearing.
The way the error is worded would make one believe it is a problem with that user's mailbox size but clearly that is not the issue. Can anyone give any insight or suggest where I should troubleshoot next on either the Exchange Server or on the user's computer?