title: Google Apps mailserver - works fine for < 50 messages; problems when sending more
body: <p>My asp.net (mvc2) web app webinar registration system sends emails with connection info. Currently we just loop thru the list of attendees and hit a System.Net.Mail.SendMail for each. We send mail via our GoogleApps account (non-premium).</p>
  
  <p>My use case is to send &lt; 50 emails at a time and the system's been working fine. On the occasions where the number pushes a 100 addresses I find error returns with the message:</p>
  
  <p>Service not available, closing transmission channel. The server response was: 4.7.0 Try again later, closing connection. (MAIL) g31sm4823143ibh.4</p>
  
  <p>Is this message specific to Google's servers (searched on the phrase - seems like 'no'). Is there a recognized 'best practice' for sending emails by code? </p>