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Office365 Spam Filter Settings

qvfps asked
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.
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Hardware Tester and Debugger
@qvfps Hi there! :)

When this "Mark bulk email as spam" is enabled/checked, email identified as bulk at or above the specified threshold will go through the specified spam filter. This threshold is based on the BCL of an email. BCL indicates how likely the email is to generate a complaint based on the sending practices of the bulk email sender. For example, selecting 3 treats email with a BCL of 3 or higher to be treated as spam.

Examples of bulk email include newsletters, social updates and promotions. Other reasons might be the recipient is not supposed to receive this mails, maybe in the form of updates, as often which might be it was blocked for this sender. It might also be because they want to keep a cleaner and more organized inbox. You may refer to the following article posted by the official Office 365 team on more information regarding enhanced bulk mail control.

Block spam this holiday season with the new enhanced bulk mail experience in EOP
Most Valuable Expert 2015
Distinguished Expert 2019

Best thing to do here is run a message trace, it will give you the exact reason why the message was blocked. You can also look at the header info for additional details. Once you have the reason, you can adjust settings as needed.


Thanks.  I have already run a mail trace and was looking for a reason.   No where in the results did I see a reason for it being classified as spam.   It is similar to several other emails which were delivered except for the number of recipients on the email.     I went through the headers and the only thing I saw was the sender does not have spf records but all but one other email from the same address were delivered without issue.