Category: Authentication
Why did my email messages to Gmail receive a “421 4.7.30 This mail has been rate limited because DKIM does not pass. Gmail requires all large senders to authenticate with DKIM. Authentication results: DKIM = did not pass” message?
Starting on February 1, 2024, Google has imposed new requirements on bulk senders, including a…
![A diagram of how DKIM messages flow.](https://deliverabilityfaq.com/wp-content/uploads/2023/05/640px-DomainKeys_Identified_Mail_DKIM.svg_.png)
What is DKIM?
DKIM, short for Domain Keys Identified Mail, is an email authentication technology used to help…
![A hand holding picture identification, showing how an SPF record is authentication, similar to picture ID.](https://deliverabilityfaq.com/wp-content/uploads/2023/05/photo_2023-05-04_16-44-21-1024x1003.jpg)
What is SPF?
It’s not Sun Protection Factor, SPF stands for Sender Protection Framework. SPF is one of…