My father in law's Windows Live Mail began having troubles logging into his yahoo email account yesterday.
The typical authentication error appears below...
But this doesn't appear to be a simple password issue because he can log into this account through the web interface. I even had him change his password and then apply this password to the POP3/SMTP sections in the Windows Live email configuration.
All the Yahoo email settings were verified, at least, 4 times so it doesn't appear to be a settings issue. Additionally, his Live Mail program is successfully sending/receiving email from another Yahoo account, as well as GMAIL, and HotMail.
Saving the best for last...
This account was successfully phished yesterday! My father in law received a Yahoo'ish looking warning email telling him that his account was compromised. Unfortunately, he dutifully followed the instructions and gave these a-holes his password. I am only adding this to give you full details but I don't think this is the source of the problem because:
a) I had him change his password
b) He can log into his Yahoo email through the web interface
Thank you so much!
Unable to send or receive messages for the Yahoo (*********) account. An incorrect password was entered. The next time you send or receive messages, you'll be asked to enter your user name and password for this account.
Server Error: 0x800CCC90
Server Response: -ERR [AUTH] (#MBR1240) Please verify your account by going to https://login.yahoo.com
Windows Live Mail Error ID: 0x800CCC92