WLM Error Message????

In the past couple of days I have had the following WLM error message:

The message could not be sent. The authentication setting might not be correct for your outgoing e-mail [SMTP] server. For help solving this problem, go to Help, search for "Troubleshoot Windows Live Mail", and read the "I'm having problems sending e-mail" section. If you need help determining the proper server settings, please contact your e-mail service provider.
The rejected e-mail address was 'chrisharley@shaw.ca'.
Subject 'New Christmas Tradition'
Server Error: 452
Server Response: 452 4.1.1 <chrisharley@shaw.ca> requested action aborted: try again later, too many recipient per hour
Server: 'smtp.telus.net'
Windows Live Mail Error ID: 0x800CCC79
Protocol: SMTP
Port: 25
Secure(SSL): No


I don't understand the line "try again later, too many recipient per hour"

Is that the server saying they have too many emails to post or is it my problem with too many recipients on the email. I regularly send emails to two groups of 276 and 210 recipients with no problems. Lately it has been refusing to do this. Any ideas? I have not changed any settings.
Thank you for any help.

Thanks Roderunner,
But then I get this error message:

The connection to the server has failed.
Subject 'New Christmas Tradition'
Server: 'smtp.telus.net'
Windows Live Mail Error ID: 0x800CCC0E
Protocol: SMTP
Port: 465
Secure(SSL): No
Socket Error: 10061

Try port 587:Solved: Windows Live Mail Error 0x800CCC0E - Tech Support Guy Forums
"Problem is solved. It did require SMTP setting to be 587 and did require Authentication to be enabled. In addition, I made an error while re-entering the output server address by omitting one letter which complicated the correction process."