Same thing is happening to me except I can get 5 sent before an error.
Currently using TLS on port 587 to talk to an Exchange 2010 server. All other SMPT options that I've tried fail completely.A server script in a database is supposed to send out 10 emails to different people. Whether it's run by server or client, I get an error for any attempt beyond 5. If I wait (~30s), I can send 5 more.It seems like there is a limit somewhere on how many email I can send. Trying to hunt that down....Mike