I have not changed any settings, I've spent time on the phone with Comcast and they said it's the email client. The thing is I haven't touched my email client. I can recieve email, but I can't send. It keeps telling me SMTP server rejected the email. I do not have any anti-virus programs running. Sometimes I can create a new email and it will send fine. But I can't reply to an email. I'm pulling my hair out this is so frustrating!