Are you witnessing the error code 550 in the SBCGlobal Email? If yes, then this issue is related to the email address of the recipient and can occur because of the following reasons:
• When the email authentication has been blocked.
• If the user is sending the emails from the incorrect email address.
• It occurs even when then the person is trying to send the email to an incorrect email address.
Once you know the reason, then you are free to resolve the issue on your own. Moreover, you can reach out to experts by calling SBCGlobal support number which stays accessible round the clock in a year. Read more for : SBCGlobal customer care number | SBCGlobal customer service number