occupies the "gray area" between wanted personal correspondence and unwanted spam. Unlike spam, which is unsolicited and often malicious, graymail comes from legitimate sources that have obtained consent at some point—such as through a purchase, a newsletter signup, or a white paper download.
You might wonder, "If they didn't mark me as spam, does it matter?" graymail ppv
+ PPV = Postmaster Policy Violation :
Could you clarify your exact use case?