I successfully sync'd my iPhone with my iMac (a very painless process, by the way). I can surf the net and get e-mail from Comcast.net through my wireless network at home (Airport Extreme), but I cannot send e-mail. I get an error that the "sender address was rejected by the server." I called Comcast, but they could not help. I have searched Comcast and Apple FAQs to no avail. Can anyone help with this problem?
Make sure that your POP account info on the iPhone (Go to Settings-->Mail--->POP account) has your username and password entered in the Outgoing Mail Server section too. I had that problem with my Comcast iPhone email and once I entered that info, everything now operates properly.
I am having similar problems. I can receive email but it will not send. The error reads - "the connection to the outgoing server "smtp@comcast.net" failed. The SSL is on as you suggested. The account is working fine through Outlook