If you are using the SMTP2GO service to send out-going emails, to improve the deliverability of emails so they don't land in the Junk-mail inbox, you will need to add CNAME records to your domain host service provider.

Your domain needs to be added to the 'Verified Senders' function in SMTP2GO > Settings, then make the changes to your DNS host.

For example

In order to improve your delivery rates, we always recommend creating an SPF record and a DKIM record in your DNS settings. By doing so, this tells the recipient server that you have given our servers permission to send on your behalf. Without these small changes, recipient servers may flag your emails as spam and either dump them in the junk folder, or else just not accept them at all.

SPF (Sender Policy Framework) records tell the recipient server that you have given SMTP2GO’s servers permission to send on behalf of your domain name. A DKIM (Domain Keys Identified Mail) signature digitally signs your emails so that your particular domain name can claim responsibility for the email sent. If you haven’t set up a DKIM record, SMTP2GO signs your emails with our domain name. Gmail recipients will see that emails are sent “via smtpcorp.com” or “via smtp2go.com” and you may experience some issues when sending to some recipient servers such as Hotmail/ Yahoo/ Gmail and AOL. If you need to set up a DMARC record (which is useful to prevent spammers sending phishing emails from your domain name) then you will absolutely need to create a DKIM signature.