IMAP on iPads and iPhones not getting response from Comcast mail servers
After numerous hours of attempting to configure Comcast email on two iPads constantly getting 10 minute "verifying" and then an error message that iMAP could not connect to imap.comcast.net I learned the reason. I was doing these operations on my AT&T home network. Taking the iPad to a friend's house who has Comcast as their ISP, the iPad Comcast email account verified and worked almost instantly. Comcast email configuration does work on wired LAN's on a PC in Thunderbird--just not on wireless iPads.
On one site, I read only one reference to the effect that Comcast blocks configuring their email on non-Comcast networks. This limitation has caused many people around the US to endure numerous hours of frustration. When customers ask for help from Comcast, they get no satisfactory answer. I spent a few hours reading those complaints on various web sites related to this problem.