I have a desktop mac with OS X 10.8.3 operating system. I recently upgrade to Mountain Lion.

I use Outlook Office for mac 2011 to receive/send emails. For the last four days I haven't been able to send mail, only receive. Whenever I try to send an email I get the following error message.

"Cannot send mail. The SMTP server does not recognise any of the authentication methods supported by Outlook. Try changing the SMTP authentication options in Account settings or contact your network administrator"

Why is this happening and what do I do to change the settings?