Invalid Username??

Invalid Username??

After installing the Zoho Calendar Plugin for Microsoft Outlook, I receive an "Invalid Username or Password" error while trying to login through the plugin using my username@zoho.com credentials. I use these credentials obviously to login to zoho.com, etc... so I can't understand why I am receiving this error.

Has anyone else come across this? I am using Outlook 2007 on Vista x64. Thanks!

Tommy