What's Causing This Error
The SPF authentication failure error may occur due to multiple reasons, such as:
- Unable to resolve the domain name within the DNS.
- SPF record was not present for the domain.
- SPF record contains invalid syntax.
- The IP address is not listed in the SPF record.
Solution - Here's How To Resolve It
Follow these steps to resolve this issue:
- Ensure that the domain name is resolvable.
- Ensure that the domain contains valid SPF records.
- Ensure that the SPF record does not have any invalid syntax.
- Ensure that the SPF record includes a valid IP address.