Error: Bad SenderBase Reputation Score
Our inbound mail servers use IronPort's SenderBase network to determine how to treat incoming SMTP connections. For each IP address it knows about, the SenderBase network assigns a reputation score, ranging from -10.0 to +10.0. Negative reputation scores are bad, and positive reputation scores are good. Our system then classifies each incoming SMTP connection based on the reputation score for that IP address.
Note: ITS does not publicly document the exact ranges of reputation scores used to classify connections because they are subject to change.
Servers with extremely negative SenderBase reputation scores are not allowed to connect. ITS has never received a complaint of a server being improperly rejected based on an extremely negative SenderBase reputation score.