Last week, I was working on configuring File Server Resource Manager (FSRM) on Windows Server 2008R2 but I noticed I wasn't getting any emails. Luckily there's a built-in "Send Test Email" button but it thru a less than helpful error:
To find more details, I opened up the event viewer to see these details:
Error: IFsrmEmailExternal::SendMail, 0x8004531c, Mailbox unavailable. The server response was: 5.7.1 Client does not have permissions to send as this sender
No permissions? That's odd since I had the IP address of the server added in Exchange to allow unauthenticated SMTP connections. Well it turns out that FSRM uses the server AD computer account credentials to send the emails!
The fix was rather simple. Open up the Exchange Management Shell and run the following Powershell cmdlet:
Add-ADPermission -Identity "MailboxName" -User "domain\ComputerName$" -ExtendedRights "Send-As"
Make sure you do this to the mailbox name of the email address you specified in the "Default From e-mail address" field in the FSRM email configuration panel. Hope this helps!