It looks like a lot of people are having this problem. I have three Yahoo! mail accounts on my Droid X. Two of them are working fine. On one of them, it was recently hacked so I changed my password about 12 hours ago. I have successfully logged in via PC and also added the new password to my iPad with no problems. But, with my Droid X, I kept trying to access the account with the new password and it keeps saying that the login information is incorrect. I deleted the account and re-added it, and it says" Error! Login to the account failed. Please try again." It's been saying this for the past 12 hours. I also tried removing the account again and adding it as a standard email account but to no avail. However, I can go onto the browser on my Droid X and get into the account.
Go into your Settings-->Applications-->Manage Applications-->Select All Scroll to Email Enter an Clear the Cache and Data Hit the Home Button then Pull the Battery Hold your Power button for 20 Sec. then Re-insert the Battery power up try the Your Yahoo account Again Use lower case Letters..
Thanks - so, after I do that, will ALL of my email accounts disappear? I have an IMAP email account for work as well as some gmail and other Yahoo! accounts. Is I Clear the Data, does that mean I have add them all back again?