User ManualSubscribers Subscriber DocumentationWhy am I getting warnings about spoofing and fraud detection

Why am I getting warnings about spoofing and fraud detection

Traditionally, mailing lists have always had the Sender's email address in the From: header

So people will know who each message is from, without having to open it.

These days, ISP's expect that email for a person will only be sent from their ISP. Mailing lists are an exception to this.

Some ISP's will include a warning in the emails that you send to your mailing list.

This sender failed our fraud detection checks and may not be who they appear to be. Learn about spoofing.

Microsoft Office 365 Email services does this for instance.

The mailing list has the sender's address in the From: line

When the ISP sees that a message is From themselves, and from a different ISP (, they insert the warning at the top of the message.

You can ignore this message if you recognize that it is a message that you sent to the mailing list.


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