Removing the “Sent on behalf of” Header

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When sending email campaigns from our hosted service, you may find that an additional header is added to outgoing messages, at the top of each message. The “From” area will show the name of your account with us and the domain name of the mail server that sent the message, followed by the words “sent on behalf of,” which is then followed by your specific From address that you entered in.

Below is a screen shot showing an example of this message as it appears in Outlook.


Why Does This Header Exist?

Though you may wish to remove this header right away, it is important to understand why this header is present.

We allow all of our clients to enter any email address they like as the “From” sender address for each campaign — however, this also means that the emails you send using our hosted system will actually be sent from a different domain (one of our mail servers) than the domain that is listed in your custom From address. In the above example, you’ll see that though the From address was set to “,” the email message actually originated from a mail server with a domain name of “”

When emails are sent with a From address that differs from the address of the actual mail server, this can be seen as an attempt to “spoof” or “fake” the origin of the email. Unfortunately, faking the From address of an email is a common tactic that spammers use, especially in “phishing” schemes, and so many email service providers will block these types of messages, perceiving them to be spam.

In order to help ensure that your campaigns are not perceived as spam, we add the “sent on behalf of…” header, to show that the email was sent from a legitimate source. This helps to keep your messages out of your subscribers’ spam folders.

Can I Remove The Header?

The “sent on behalf of” text in your message header can be removed, yes. This will make the heading of your messages appear a little more clean, and only your own From address will be displayed — the name of our mail server will not be displayed.

This setting can be turned off on the Settings page. To see this option, log in to your account as the “admin” user, and click the Settings tab. Then, scroll down to the section called “Deliverability Tools.”


Uncheck the “authenticate all outgoing emails” box, and click Save Settings. If you do this, the “sent on behalf of” text will be removed from all outgoing emails. (Note: the “sent via…” header will always appear in messages that are sent to addresses. This is actually a security feature that Gmail imposes, and cannot be influenced or disabled by us.)

If you choose to disable this feature, please understand that it may have a negative impact on your deliverability rate, which could in turn also affect your open rates and click rates. Disabling email authentication is done at your own risk!

The kind of impact that disabling email authentication will have can vary from person to person. For example, if you have a high quality list of double opt-in subscribers, healthy sending habits, and well-written content that your subscribers are interested in receiving, you may not notice much of a reduction on your delivery rates. However, if your message has a high spam score, your list is outdated, your sending habits are very infrequent, etc, disabling this feature could hurt deliverability even more.