550 5.7.1 Message rejected as spam by Content Filtering

Products

• Email Security.cloud

Issue/Introduction

The sender is receiving a bounce back with the error "550 5.7.1 Message rejected as spam by Content Filtering"

Error: "550 5.7.1 Message rejected as spam by Content Filtering"

Cause

This error is generated when the recipient mail server is using Microsoft Exchange content filtering. MS Exchange servers have built in filtering features that can block certain emails if they match their content filtering rules. Email messages that are empty in content (or nearly empty) may be caught by one of the default filtering options. This error is generated by the default-enabled Content Filtering anti-spam option under Hub Transport > Anti-Spam in the Exchange configuration.

Resolution

Steps for the administrator of the recipient server to resolve the issue:

1.     From the Exchange program group:
2.     Open the Exchange Management Console. Next, depending on the server type, select either of the two options below
               - Microsoft Exchange | Edge Transport | Anti-Spam
               - Microsoft Exchange | Organization Configuration | Hub Transport | Anti-Spam
       All of the filter types are enabled by default
    
3.      Open the Content Filtering Anti-Spam filtering type and go to the Action tab.
4.      Then uncheck the box next to "Reject messages that have SCL rating greater or equal to:"