This did not work because the Yahoo password is not stored on the device after being entered. Apparently Yahoo has something called XYMCOOKIE authentication for

This did not work because the Yahoo password is not stored on the device after being entered. Apparently Yahoo has something called XYMCOOKIE authentication for SMTP and IMAP which is basically just acceptance of a pre-sent hash/cookie. The iPad discards the actual password the first time you enter it and instead stores a XYMCOOKIE. See here: https://www.google.com/search?q=XYMCOOKIE+authentication https://www.google.com/search?q=XYMCOOKIE+authentication