We use thunderbird, as our default email client, to move email from our db software to salespeople, customers and vendors. Up through mid-May all emails were sent (and received) as intended. Mid-May, first thing in the morning, I would see a error on the server stating: an error occurred while sending mail: "The mail server sent an incorrect greeting. Too many concurrent SMTP connections from this IP address; please try again later..." It is only the last few emails at the end of a db routine that do not send. I updated thunderbird, no change. Any suggestions?