1. Log into your cPanel account.

2. Scroll down to "Mail" section and click on "Forwarders"

3. Under "Email Account Forwarders" click Add Forwarder.

On the Add a New Forwarder page:

1. Enter the email name and select the domain for the address.
2. Select Discard and send an error to the sender (at SMTP time).
3. Enter the failure message you would like users to receive.