What do you mean by "linking" your Comcast account? To what? How are you using the account on the phone----------using Safari and the webmail UI? Or the Mail app that comes in iOS? Or the Xfinity Connect app?
I want to link it to the mail app that comes with the iOS. I have the iCloud and gmail accounts linked in the mail app I wanted to add Comcast to it as well
I've got two of my Comcast accounts enabled in the iOS app (iPhone) and have never been prompted for a PIN. If you access using Safari and the webmail UI does it work OK?