Got an error while using MS Outlook for Mac 2011

It was my first time to use Outlook for Mac 2011 and I was then configuring it when I got this error message, see below.

Mail could not be received at this time.
The server for account ”**********” returned the error ”authentication failed.” Your username/password or security setting may be incorrect. Would you like to try re-entering your password?
I am not that techie so I need someone to guide me on how to resolve this error.
Can any expert in this forum help me?
