Error occurs when sending - ControlMessages ProcessMessages: Parser Error

The following error message is received when sending a mail - ControlMessages ProcessMessages: Parser Error.

A mail has been sent to the address of the REDDOXX engine (ex. engine@local), meaning that the mail does not come from the REDDOXX portal and contains no useful information (Parser Error).
The problem is that a "real" e-mail address has been entered for the engine and needs to be changed to an engine-only address.

Enter an engine-specific mail address which is only used for the REDDOXX engine.