SC provides a mechanism for sending alerts via SENTRAP parameter and success messages vis SUCCESS_TRAP parameter
You can use anything you want, %MSG will be either the success or error message
Your issue it looks like is you didnt specify email address (email@example.com) and SENDTRAP is there twice (SENDTRAP=SENDTRAP=). If I was configuring this I would do following (please try this, with your email address instead of mine):
I think you can also go with something like your command example to put %MSG in the email body instead that having it in the subject and passing the ERROR or SUCCESS in the Subject as your example with /bin/echo, probably it should work and it can be more readable.