Common Reasons for Email Deliverability Issues

James Burke
James Burke
  • Updated


In this article, we will explore the common issues that can impact your email deliverability and how you could solve them. 


IP Warming

Mailbox providers are suspicious of emails coming from an IP that has no reputation or that has an unfamiliar sending pattern. IP warming is the practice of gradually increasing the volume of mail sent with a dedicated IP address according to a predetermined schedule. This process helps to establish a reputation with inbox providers as a legitimate email sender. If you immediately begin sending large amounts of mail, you will risk having your messages blocked by inbox providers.


Mailbox Security Features

Our external inbound email processor has two main security features that may impact deliverability, DMARC compliance and DNS SPF. 

A sender policy framework (SPF) record is a type of DNS Text record that lists all the servers authorized to send emails from a particular domain. For emails to reach your mailbox a valid SPF record must exist for the sender address on the SMTP server it has been sent from. 

DMARC is an email validation system that helps ensure that emails are sent only by authorized users. DMARC policies dictate what servers should do with emails that fail SPF and DKIM checks. In the case of our external mailbox provider, emails that fail a DMARC compliance check are rejected. 

Both of these security headers are present in each email you send and can be viewed by examining the HTML headers of an email. This can be done using a text editor.


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