I had that too and would get logged in sometimes by adding @yahoo.com to the user name. Still had problems so I upgraded to the newest version and it works fine now.
Glad to see I�m not the only one having that problem. In the last five days I�ve not been able to access the application, but can log into Yahoo via the web. Hopefully someone will put something out on the issue.
Ive been having the same problem with YIM on my Pearl. I know it started acting up the last few days. I even reset my password, just in case, and still hasn't worked.
I had that too and would get logged in sometimes by adding @yahoo.com to the user name. Still had problems so I upgraded to the newest version and it works fine now.
That's my next step - to upgrade. Hopefully, that'll fix it on my end as well.