When you create a ticket through mail eater, the ticket is created but with a blank description (which causes the content or body of the email to be completely disregarded by Service Desk).
This might happen if the email is not in Plain Text format.
The mailbox which Service Desk mail eater is configured to use must be set so that it receives emails in plain text.
If using Microsoft Exchange, you may do this by changing the following setting in Exchange for the specific mailbox:
"MIME format for Message in the protocol property settings for the User account - Set to Plain Text"