error: 550 5.1.1 User unknown

error: 550 5.1.1 User unknown

Hi

 I am having problem with my email . It doesn't receive emails.

 says the address doesn't exist.

This message was created automatically by mail delivery software.

 A message that you sent could not be delivered to one or more of its recipients. This is a permanent error.

 ja@domain.com, ERROR CODE :550 - 5.0.0 Invalid Recipients.