Receiving both comcast.net and gmail.com email accounts through Windows Live Mail and suddenly there is a yellow alert in the taskbar of my WLM

window and an error window telling me 

An unknown error has occurred.

Subject 'before I pack my calendar'
Server: 'smtp.gmail.com'
Windows Live Mail Error ID: 0x800CCC0B
Protocol: SMTP
Port: 465
Secure(SSL): Yes

This is not allowing me to send mail!

I'm using a Dell Inspiron 5720...( 64 bit)

Internet Explorer 9

Windows 7 Home Premium,  SP1

Please tell me how to fix this without spending anything more than I already have,  and keeping tech jargon understandable,  please?

Thanks in advance

delraybuzz