Cannot login to IMAP after upgrade

Upgraded my Macbook 15 retina to Yosemite but mail cannot connect to IMAP server.

SMTP seems OK.

I've deleted account and re-entered it. It IS correct but it refuses to connect.

Says Trying to login to this IMAP account failed. Verify that the username and password are correct.

Any ideas?

iPhone 4 and iPad Air mail working OK still.