I am trying to set up my google supported domain email account.  I set it up like a regular gmail account and it doesn't work - "unable to establish a securer connection"  Comcast is my ISP.  Any ideas?

Thanks

Kirsten
This is happening on both my MacBook Pro and my iMac.  I have been to the Apple store 3 times in the last three weeks to try to resolve.  I have called Comcast, the internet service provider.  They claim it is not them. My family uses PCs and are not having any problems.  Any suggestions?

Regardless of what program I'm using, Every time my computer searches for new emails on my gmail account (every 15 minutes), I get an error message. "Some errors occurred while processing the requested tasks. Please review the list of errors below for more details". Yet there are no errors listed. I've spent about 7 hours with H/P and another five hours with Comcast (former email provider) and still have not resolved this issue. 
My version is 14.0.0. Mac can't help, RCN can't help.....I can send and receive from my iPad.  Just now my incoming mail quit on my Mac as well.......
I cannot send any type of attachment with my emails.
The recipient gets several copies of the same email and none can be opened.

My Windows Live retrieves messages from Comcast.net.  When sending emails
from the Comcast page the attachments go through....but I would like to correct my problem
and keep using my Windows live.

Thanks!
Have been working with Comcast for 4hours trying to get and send my E-mail my wife can receive hers but can't send. Comcast said to contact Microsoft live mail
we need your help

Bud

Have been working with Comcast for 4hours trying to get and send my E-mail my wife can receive hers but can't send. Comcast said to contact Microsoft live mail
we need your help

Bud

An unknown error has occurred.

Subject 'test'
Server Error: 554
Server Response: 554 omta02.westchester.pa.mail.comcast.net comcast Port 25 not allowed - http://customer.comcast.com/help-and-support/internet/email-client-programs-with-xfinity-email/
Server: 'smtp.comcast.net'
Windows Live Mail Error ID: 0x800CCC6F
Protocol: SMTP
Port: 25
Secure(SSL): No