Can't get my Comcast password to work on SMTP outgoing email using iOS 11.0.3 on both iPhone 7 and iPad. This just started being a problem a few weeks ago. Maybe concurrent with iOS upgrade? Thanks.
In iOS, you need to set the password in two places------for the incoming server, and then again for the outgoing SMTP server. Did you do that? If not, to change it for the SMTP server;
In iOS 11 go to "Settings" on the home screen, then scroll down to"Accounts & Passwords", click on the account, and then on the next screen tap the "account" again. Scroll down to "SMTP" and tap that. Then tap "smtp.comcast.net" again. On the next screen, tap "smtp.comcst.net", and you will see the password. Change it and then tap "Done" in the upper right-hand corner of the screen.
I've got two Comcast accounts enabled on my iPhone, and have not experienced any password issues with either one of them. I'm running the latest version of iOS-11. What happens when you try to send? Are you getting any error message?