For example: When I send an email from my [email protected] account, the recipient receives it as an [email protected] account. As a result, when the recipient tries to reply to my email, they usually end up receiving an "undeliverable" message shortly after sending the email. My internet service provider is Comcast, but that is not even my email address with Comcast. I have had my iPhone for a couple of years and this is the first time this is happening. I have not made any recent changes to my settings. Thanks, David.