We are running Exchange 2013. Some of my users are telling me that they are sending messages but the recipients are not receiving them. I have check the delivery reports for some of these email messages that are not being received and they are all show the following:
2/26/2018 1:17 PM SVR-EXCHANGE-01
The message was submitted to svr-exchange-01.ad.mydomain.com.
2/26/2018 3:59 PM SVR-EXCHANGE-01
Message delivery is taking longer than expected. There may be system delays. For more information, contact your helpdesk.
When I go into the Exchange Queue Viewer, there are no messages in the queue.
This is happening to a lot of email being sent externally. Any ideas?