Email deliverability is a complex multidimensional subject. There are literally hundreds of factors that you need to consider in order to improve your email delivery rates. The good news is that most of these factors are under your direct control.

First, it is absolutely essential that you have valid SPF and DomainKeys records for your domain. Basically, they tell spam filters that you have the rights to send email from Please contact your email administrator or provider for help with creating SPF and DomainKeys records. This will solve most – probably all – email delivery problems that you may currently experience.

Second, professional email marketers always check each newsletter and autoresponder template against a wide range of spam filters before sending, and make necessary adjustments. A service like Litmus will help you test your emails against all major spam filters at ISPs and webmail providers, as well as corporate filters.

Every Relenta account comes with a default SMTP server, so that you can start sending emails right away. Most of our customers have used it for years without any issues.

We use every reasonable precaution to ensure that emails sent via our default SMTP reach their recipients. For example, we regularly whitelist with all major ISPs and ensure that our IP address ( isn’t blacklisted in any of the antispam databases. You can check its current status for yourself here:

If you’ve added SPF and DomainKeys records for your domain, tested against spam filters, and still aren’t happy with the results, you may want to consider adding your own SMTP. It can be from your existing provider, such as Gmail, or specialized services such as AuthSMTP, Dyn,, TurboSMTP or SendGrid. These companies may be able to give you email delivery guarantees and provide consulting. We are not affiliated with any of these services.