My Comcast email on my MAC stopped working over the weekend - it still worked for my iPhone. Turns out that my email settings somehow didn't work anymore... after making the recommended changes - everything is working!
The Comcast website @
Using Email Client Programs with Comcast Email
recommends the following
Incoming Mail Server - Name: mail.comcast.net
Incoming Mail Server - Port Number: 995 (POP3)
Outgoing Mail Server - Name: smtp.comcast.net
Outgoing Mail Server - Port Number: 465 (SMTP)
SSL Encryption: checked
Authentication: Comcast ID and Password required
Note: if your not comfortable with tweaking your computer settings then call Comcast!