Be aware, however, that the effectiveness of this method is limited.
Email services and servers may bypass much of theemail delivery processfor messages to recipients at the same server.
If you don’t, it’s easy and free to set one up with services such asGmailandYahoo.

Lifewire
A message sent to an echo mailer is bounced (or echoed) back to where it originated.
This makes spotting possible errors or oddities easy.
Echo mailers to try include: