The Apex Class selected is not valid. An Apex Class that implements the Messaging.InboundEmailHandler interface must be selected.

You are configuring an Email Service on Step 1 of the Email to Case Premium Setup Wizard and encounter this error: The Apex Class selected is not valid. An Apex Class that implements the Messaging.InboundEmailHandler interface must be selected.

Symptoms
Solutions
Status
Additional Information
Title
The Apex Class selected is not valid. An Apex Class that implements the Messaging.InboundEmailHandler interface must be selected.
URL Name
The-Apex-Class-selected-is-not-valid-An-Apex-Class-that-implements-the-Messaging-InboundEmailHandler-interface-must-be-selected