A call was logged today on the helpdesk system at work saying that external emails for a particular company wern’t being recieved, however when users were emailing each other internally, it was working fine.

I checked the usual things on the server such as Microsoft Exchange services, they were all up and running. Checked firewall, nothing had changed previously so that couldn’t have been the cause. When sending a test email from my works account to the customer, no NDR’s were being created, so in theory the email wasn’t even trying to be delivered. This is when I used trusty http://www.testexchangeconnectivity.com

Once I carried out a test on this, the following error was shown:

4.3.1 Insufficient system resources

I checked the storage on the C drive of the server and nothing seemed out of the ordinary. It just so happens that the Microsoft Edge Transport service will stop delivering inbound internet email if the disk space where the queue resides drops below a certain point.

To fix this issue, carry out the following steps:

– Stop the Microsoft Exhchange Transport service

– Move the folder C:\Program Files\Microsoft\Exchange Server\TransportRoles\data\Queue to a location to another drive with more space

– Edit the EdgeTransport.exe.config which lives in C:\Program Files\Microsoft\Exchange Server\bin

– Edit the following lines to point to the new location of the queue folder.

<add key=”QueueDatabasePath” value = “…” />
<add key=”QueueDatabaseLoggingPath” value = “…” />

Following this, start the Microsoft Exhchange Transport again, and check mail delivery.

Please note that the new queue location must have the following permissions set:

  • Administrators – Full Control
  • System – Full Control
  • Network Service – Full Control