i was asked to see why an email was not delivered and update the spam filter so similar emails do not get blocked.
In looking through the Spam filter I see that under Bulk Email, Mark bulk email as spam is checked and the threshold is 3.
What exactly does the 3 mean is this just a scale of how certain they are it is a bulk email or the number of recipients. The email in question had several recipients and it was the only one blocked for this sender.