Mac OS Mail Unable to verify account name and password
I tried to use an earlier answer to this problem:
"In the Mail app menu, go to Window > Connection Doctor. For each item that has a red dot next to it (there should be two for each email account, one for SMTP and one for IMAP/POP), double-click it and enter the password in the relevant box. If this doesn't resolve the issue, reply with the text in the "Details" column of Connection Doctor as this will help to give an idea of the specific problem you are experiencing."
But when I get to the Connection Doctor window and double-click the bad account (or ANY accounts) there is no field into which to put the password! The Accounts window has the Server Settings tab chosen and "Outgoing Mail Accounts" is correct. And there is nothing below that. What is wrong, please?
BTW, this one account became unreachable suddenly, with no understandable cause. It just stopped receiving mail and notifications popped up.
OBS, MacBook Pro (15-inch Mid 2010), macOS Sierra (10.12.6)