Turn on email debugging for DmLogger. Look at the Help topic for EMAIL (topic ID DMD068) and then look for the section on DmLogger.
The easiest way to debug EMail is
1. go to the EMAIL instruction in your program.
2. float your cursor over the wrench in the top right corner of the EMAIL instruction in the ladder view (the wrench is context sensitive tools that is instruction/instance specific)
3. In the menu, select Enable PLC Message Dump (should be the top entry in the tool context menu)
4. You want to turn ON ST36 to Enable Message Dump (per the Help topic mentioned above)
5. Make sure the Message Level is set to 1 (0 won't log anything, 2 is too too much - only useful to see details, but this bogs down the PLC, your network, your PC; the default Message Level is 1).