550 5.2.0 STOREDRV.Deliver: The Microsoft Exchange Information Store service reported an error. “MapiExceptionNotAuthorized”

This morning I’ve been troubleshooting an Exchange public folder related issue that had me baffled for a little while.

Users could send e-mails to a public folder internally, but any external e-mails wouldn’t arrive in the folder. After running through message tracking I found the following error in the tracking logs:

550 5.2.0 STOREDRV.Deliver: The Microsoft Exchange Information Store service reported an error. The following information should help identify the cause of this error: “MapiExceptionNotAuthorized:”…

Knowing that internal users could e-mail the public folder, and knowing that the e-mails were reaching the Exchange server meant that I had to be dealing with a permissions based issue. When I looked at the public folder’s MAPI permissions using Powershell (get-publicfolderclientpermission is the cmdlet for that one) I could see that the folder was set to “Anonymous: None”. This means that anonymous senders don’t have rights to create a new item in the public folder, and so the 550 5.2.0 message is logged.

To get around this issue, you need to add at least the “CreateItems” access right for the Anonymous user. You can do this within Outlook looking at the permissions, or, in PowerShell as follows:

add-publicfolderclientpermission -identity "\PathTo\PublicFolder" -accessright createitems

To check this afterwards you can perform the following script:

get-publicfolderclientpermission -identity "\PathTo\PublicFolder" | where {$_.User -match "Anonymous"} | fl