Cant send emails in Outlook

Hello,

i have a problem sending my emails from Microsoft Outlook 2010.
I have to log into my gmail account in order to send emails but I can receive emails fine in outlook. Once I send the email online gmail, it shows in my outlook sent box.

This is the error I get:

Task '***@*** - Sending' reported error (0x8004210B) : 'The operation timed out waiting for a response from the sending (SMTP) server. If you continue to receive this message, contact your server administrator or Internet service provider (ISP).'

I checked all my settings via my gmail settings configure instructions and all is fine, even when I do a test, I get no errors and microsoft sends me a emails saying the test was successful.

Please can you assist