Error: SPF fail-unaligned

What's Causing This Error

Typically, this error occurs when the SPF alignment mode is strict. The most standard configuration for the SPF is "relaxed"; however, setting the SPF record to "strict" can cause the SPF validation to fail if the return-path domain is a subdomain of the root domain.

Solution - Here's How To Resolve It

The most common way of handling this error is setting the SPF alignment to "relaxed", where even subdomains may pass the check.

However, if this is impossible, the user can configure a DMARC record for the domain. While this does not make the SPF check succeed, the email server validates the DMARC record and delivers the email to the recipient.