We are using SMSSMTP 184.108.40.206 for our gateway SMTP server and are running into issues when talking with other SMTP servers that have implemented Greylisting. The problem is not that the email is not being delivered but that the user immediately recieves a message that the delivery failed. The original message is delivered on the next delivery attempt as expected. The server itself is operating as it should but users are getting confused with the delay message.
Is there a way that I can delay the notification(such as with Exchange)? I have reverted back to having Exchange deliver outbound messages directly until I can get an answer.