SMTP2GO is an email deliverability solution. You can use the ESP (Email Service Provider) to send your transactional and marketing emails and view reports on email delivery. But before sending any email, let’s authenticate your domain by configuring SPF and DKIM records.
Your first step is to add your sender domain. To add your sender domain, please follow the steps below, and meanwhile, have a look at the screenshot.
1 - Click on the Settings on the left side of the dashboard.
2 - Click on Verified Senders from the drop-down menu.
3 - From the Verified Senders page, click on the Add sender domain button.
Once your domain is added, you will be provided with three CNAME records.
The first CNAME record in the above screenshot is for SPF.
Note: There is no need to update your current SPF record and add an include for SMTP2GO, or add it to the EasySPF, as adding that CNAME record already maps your domain to another domain (return.smtp2go.net) that has the IP addresses whitelisted in it. This allows you to have authentication and alignment for SPF without having to manage your SPF record manually.
And the second CNAME record in the above screenshot is for DKIM. In this article, we’ll show you the configurations only for SPF and DKIM without referring to the third CNAME record that is used for click/open tracking and unsubscribe links. Now let’s move on with publishing the CNAME record in your DNS zone.
Copy and paste the CNAME Record for SPF in your DNS host.
See an example of added CNAME Records in Cloudflare DNS in the screenshot below,
Now head to Managed DKIM, to add the DKIM record there, specify the Email Sender—in this case, SMTP2GO—then add the CNAME record. Finally, click the “Add” button; the system will automatically save the configuration.
When you finish publishing the CNAME records, move back to your SMTP2GO account and click on the Verify button below the records. In case you have done everything properly, green check marks will appear next to the CNAME records, which means that your domain has already been authenticated. 
You can test it with our Email Investigation tool. (See the screenshot below.)
