Secondary Email Account Not Working

I have an IMAP email account that has not been working for 3 days. My comcast.net email works, but the secondary account does not.  When I go to the Email screen, an Error message (with a red exclamation point) pops up, "Error...The provided login data to access mail server imap.comcast.net seem to be wrong. Please correct them." But I can't correct them. 

If I go into Settings/Accounts, under the secondary account name I see this message, "The entered credential or authentication information does not work or are no longer accepted by provider. Please change them." 

But if I try to change them, by clicking Edit, if I enter the password I have been using and click save, I will get a popup message, "Account Updated."  But the other messages remain.  If I try a new password it is rejected.

I have restarted the email and the PCs and phone on which the account is used, this does not fix anything. 

On the client side of this, the secondary email apps all prompt for a login, which fails. All the server port, server type, connection security settings are as recommended.

Meanwhile, I am not receiving emails to the secondary address, which is a huge problem. The chat bot does not help, so I am seeking help here.