Can't send Gmail E-mails

Hi,
I have set up my gmail account and am having issues with sending e-mails, receiving is fine.
I get the following error message:

Here is a screen shot of my smtp settings:

I have tried the diagnostics tab and it returns server not responding.
Can anyone please help?

Cheers

Sean

Hello,
try to switch in Security policy to “Use SSL/TLS on special port.” and click okay or try to switch to it and then back and then click okay

of course try diagnostics tab after.