Verified Senders

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

There is no need to update your SPF record, and you do not need to add any additional MX records beyond your existing records to use our service. View this article for the MX requirements.

You can choose to add sender domains (highly recommended), or single sender emails.

Sender Domains

For maximum email delivery rates and better branding, we recommend adding any domain names (that you send emails from) to the "Sending > Verified Senders > Sender domains" section. Adding a verified sender domain means that SPF and DKIM are automatically handled by us, and use DNS records at your own domain name.

If you're unsure what those acronyms are, you can rest assured that you won't need to learn any more about them.

Subdomains are allowed to send if the top-level domain is verified. The subdomains must exist in your DNS.

To set up a verified sender domain, follow the steps below:

Step One:

From the left-hand menu, make your way to the "Sending > Verified Senders > Sender domains" page in your SMTP2GO dashboard.

In the "Sender domains" section, click 'Add sender domain', enter your domain in the textbox and click 'Continue with this 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 Verified Senders 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 Verified Senders page will let you know exactly what you need to enter.

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


Tracking domain

The third/bottom CNAME record is the tracking domain (for any links in your email) to use secure "https" instead of "HTTP". Once the record is added and you click the blue "Verify" button an SSL certificate for the tracking domain will be requested via LetsEncrypt and applied automatically (the certificate will automatically renew).

How do I know the domain is verified and is working?

As long as your domain is showing as 'Verified' under 'Status' on your Verified Senders page, it is set up and working correctly.  



Sender Domains FAQ

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.

We'd prefer to have a hard fail (-all) with our SPF record instead of a soft fail (~all). Can we do that?

Yes, if you have a specific requirement to have -all at the end of your SPF record, then when setting up your DNS records for your sender domain, enter the value instead of

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 Verified Senders page, to see any error message in a tooltip.


Single Sender Emails

If you're unable to add/edit the DNS of your domain name, you can choose to add individual email addresses to the "Sending > Verified Senders > Single sender emails" page. You'll be sent an email containing a confirmation link which you'll need to click to activate the email address as a verified sender.

You can optionally choose to add a custom message to the invitation email, which may help the recipient understand that your business/app is sending the email (as the invitation email otherwise just contains SMTP2GO branding).

On a technical note, emails sent using a single sender email don't use the sender email's domain for DKIM or SPF, so emails will show as being sent 'via' (or another of our domains) in Gmail. We recommend adding a sender domain instead of a single sender email if you're able to edit the DNS of your domain.


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