Unable to connect to IMAP server from iPhone after resetting Xfinity password

I reset my Xfinity password this morning w/o any issues.  I updated my password successfully in macOS Mail, iPadOS Mail and then I tried to do so on my iPhone.  There, I keep getting a message about:

     Invalid Email Address

     Please enter a valid email address for this account

when I try to save my changes.

Since I hadn't touched the email field I was surprised by this but I dutifully entered the correct email address.  I keep getting the same error.  If I cancel and attempt to download mail, I get an error as the password is no longer correct.  My iPhone is running iOS 17.2 and I've also tried the same thing on an older iPod running iOS 15.8 and see the same issue.

The only difference between the mac, iPad and iPhone w.r.t. Mail is that the iPhone is using the imap.comcast.net server (the others are using POP).  I'd like to confirm that the password for the imap.comcast.net server is the same password I would use to login at login.xfinity.com.  What I've run into seems much more like an Apple problem than an Xfinity problem but wanted to see if I'd overlooked anything on the Xfinity side first before I start working the Apple side of the problem.

Lastly, having reset my password to new value, does Xfinity prevent users from resetting it back to the previous value?  That might be the simplest resolution to my problem as I should be able to switch my other devices back w/o any problems.

Thanks for any suggestions.