A domain MUST NOT have multiple SPF records.
An SPF record is a TXT record in the DNS starting exactly with "v=spf1", followed by an array of mechanisms and/or modifiers.
The multiple SPF records instance is when a domain has set up more than one SPF record. It could be due to either overlooking the first record’s existence or assuming that an association with two or more email service providers requires creating an equal number of SPF records. It gives rise to a multiple SPF records error.
Several errors trigger SPF failure, and multiple records happen to be the most common of them all. It is advisable to avoid having multiple SPF records because:
- They lead to permerror.
- They cause email non-delivery and SPF authentication failure.
- SPF lookup failure ultimately results in business loss, spam emails, and phishing attacks.