IMAP SMTP server says incorrect user name or password?

IMAP SMTP server says incorrect user name or password?

My incoming user name and password are being accepted but my outgoing smtp server returns an error saying "verify username or password" 

I am using Apple Mail in OS X 10.8, account username is the same as the incoming so I am sure details have been entered correctly :

smtp.zoho.com port 465

Any ideas why I cannot send? Seems to work fine on my iPhone with the same details.

Jason