This error occurs when the sender's domain SPF validation fails while sending an email, and therefore the recipient does not accept the email. The most common issues causing this error are:
To troubleshoot this issue, follow these steps:
View all errors
Send up to 10,000 notifications every month, for free.
Get started for free
Send up to 10,000 notifications every month, for free.
Get started for free
© 2024 Courier. All rights reserved.