Sender Domains

Update (May 4, 2022): Registering a sender domain is now a requirement before emails are allowed to be sent from that domain, for all customers joining on or after May 4th, 2022. This requirement will be rolled out to existing customers over the next few weeks.

For maximum email delivery rates and better branding, it is important to add any domain names (that you send emails from) to the Settings > Sender Domains page. Adding a sender domain means that SPF and DKIM are automatically handled by us. If you're unsure what those acronyms are, you can rest assured that you won't need to learn any more about them.

To set up a Sender Domain, follow the steps below:

Step One:

From the left-hand menu, make your way to the 'Settings > Sender Domains' page in your SMTP2GO control panel.

Enter your domain name in the textbox and click 'Add Domain'. For example, if you send your emails from then you would enter


Step Two - Login to your DNS provider:

Login to the DNS administration of your domain name with your DNS provider. If you are unsure where your DNS is hosted, check on the Sender Domains page where you'll see Your DNS provider is...

Step Three - DNS records setup:

Once you are logged into your DNS provider from step two, you're ready to create the CNAME records that are required. You do this by creating DNS records of the type CNAME for your domain name. The Sender Domains page will let you know exactly what you need to enter.

We have setup guides for popular DNS providers, which can make this easier.


How do I know it is working?

As long as your domain is showing as 'Verified' on your Sender Domains page, it is setup and working correctly.  

Step Four

To set your tracking domain (for any links in your email) to use secure "https" instead of "http", click the "Enable hosted SSL" checkbox and click "Verify". If the previous three steps have been completed and verified, you won't need to do anything else. 




We have multiple clients who will use our account. Can we tell them to use our own domain name in their CNAME records instead of

Yes - you would just need to setup CNAME records at your own domain first. For example, you could setup a CNAME record at which points to, and then you can advise your clients to enter instead. The same procedure would apply to and

I’m seeing an error with my DNS settings when trying to add the record with an underscore (_). What can I do?

Some hosts do not support underscores (_) in DNS records, and adding this record can cause an error. The underscore is required and you’ll want to contact your host and see if they can manually add the record for you or if they disallow underscores entirely.

It is still not verifying - what can I do?

One possible problem could be that you have multiple DNS servers, and one or more of them are not reporting the correct result. You can search for at MxToolbox, which will show the results from each of your individual DNS servers. Make sure to replace with the particular CNAME hostname that you are trying to verify (e.g. You can also hover your mouse over the red/orange exclamation symbol on the Sender Domains page, to see any error message in a tooltip.


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