Error message: The provided login data... seem to be wrong ???

When moving spam to my spam folder I receive a popup box with the following error message:

Error

The provided login data to access mail server imap comcast.net seem to be wrong. Please correct them.

I'm accessing mail via Chrome to https://connect.xfinity.com/appsuite/#!!&app=io.ox/mail&folder=default0/INBOX or via my iPhone mail app.  I've scoured the Xfinity forums without success, and changed my password. Under Settings > Accounts, a secondary email account shows:

The entered credential or authentication information does not work or are no longer accepted by provider. Please change them. 

A forum post from a Comcast employee (GabrielS" from two years ago seemed to address the issue.  The instructions stated to "update the password on the secondary account", followed by: "Please note that this is not changing the password for that secondary. It should only be used to update to a recently changed password." I have no idea what that means, and, in any case, it didn't work.

This morning, 17 of 34 emails in my in box were obvious spam or phishing attempts, which Xfinity should have auto directed to spam. (Yes, my spam filter is set to ON.)  This is getting difficult, and the error messages are cryptic and useless!  Kindly assist!