Hello guys, When I send e-mail to account not exist, I received messege from postmaster, like this:Delivery failed to the following recipients or group#550 5.1.1 RESOLVER.ADR.RecipNotFound; not found ## It's possible block this return message ?
The problem is: Sender is trying validate emails.They are using script. So, they send the e-mail and If received the "Message error" they understood the email is not Valid.
