When you enter the wrong email address in the senders and receivers field, the user likely encounters sbcglobal error code 550. The SBCGlobal server will notify the incorrect email id and automatically get stored in your email account's outbox. But error code 550 can be caused by blocking the email authentication. And users can apply a simple hack of entering the correct email id in the senders and recipient field and solve this error in less than 2 minutes. But SBCGlobal provides the facility to their users to call at SBCGlobal helpline number whenever they face any SBCGlobal email problem.