Configuring the DNS domain of the website from which you send your emails, inserting the SPF and DKIM authentication strings, is a critical step to make the most of turboSMTP.
Thanks to this, in fact, the delivery rate of your messages is maximized. All information can be found in our article on the "White Labeled service".
Unfortunately, several providers of websites (Aruba, for example), do not allow you to configure the DNS record, which affects badly your deliverability. If your provider also doesn't make it possible, we recommend to use a different domain from which to send, for example on GoDaddy.
On that domain you will then create a mailbox - your new sender address for all newsletters - and start using turboSMTP with it.
This trick is also very useful for those who haven't their own website but want to use turboSMTP at best, and at the same time give a more professional image to their communications - sending emails from a domain consistent with your brand.