If a send fails, the next resend time is generated by adding a random value between 3 and 9 minutes, spreading out the resend times so all the undelivered email still in the “short range” period isn't sent at the same time. If a send hasn't succeeded by the end of the “short range” period, the program will generate new send times using random values between 60 and 90 minutes. If a send still hasn't succeeded after 100 hours the email is discarded and a “return-to-sender” email will be sent. | 
