When sending your campaigns, you may find that an additional header is added to the top of your outgoing messages. In Outlook the “From” area will show the name of your account with us, the domain name of the mail server that sent the message, the words “sent on behalf of,” and your specific From email address. In Gmail there is a similar message, although the wording is slightly different:
Why does this header exist?
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 platform will actually be sent from a different domain (one of our mail servers) than the domain that is listed in your custom From email address.
Although the From address is set to anything you choose, for example “firstname.lastname@example.org,” the email message actually originates from a mail server with a domain name of something like “acems1.com.” Outlook and Gmail display a header message to tell recipients that the email was sent with a From address that differs from the address of the actual mail server, because this can sometimes indicate a message has been “spoofed” or “faked.” Since we've properly authenticated your emails, there's no need to worry about this negatively affecting your messages. This header doesn't “hurt” or “help” your deliverability, it's just an informative message to recipients at Outlook and Gmail.
Many ActiveCampaign users prefer to remove the “Sent on behalf of” header because it looks messy or may be confusing. It's very easy to remove the header and there are no negative consequences of doing so.
How do I remove the header?
The “sent on behalf of” text in your message header can be removed by setting up DKIM for your sending domain. This will make the heading of your messages appear a little more clean and only your own From email address will be displayed (the name of our mail server will not be displayed).
To setup DKIM, log in as your account's admin user, go to the “My Settings” page on the top right and then click the “Advanced” tab located on the left side menu. Choose “I will manage my own email authentication.”
There are several options on this page but you only need to setup DKIM to remove the “sent on behalf of” header. Enter your domain name in the corresponding DKIM field.
This will generate records that you can then add to your DNS as TXT records at your registrar or hosting provider (e.g. Godaddy).
Click “Save Settings” at the bottom of the page when done. Once complete, the “sent on behalf of” text will be removed from all outgoing emails that are sent using the domain you setup. Sometimes it can take a few hours for the DNS records to propagate. If it doesn't appear to be working at first, wait a few hours and retry.
For more information about DKIM and email authentication, you can read here.