I have been trying to sign into Twitter for days. It clicked that maybe two-factor was the issue today, so I disabled it and changed my password. Still get the same bloody error: Unable to verify account name or password. Could someone sign out of Twitter on their Mac, change the password, enable two-factor and tell me if you can sign in? Then do the same as me? I'm convinced it's two-factor screwing things up. Note: This is via Settings > Mail, Contacts and Calendars > Twitter.