Subdomains are less protected than the domain
URGENTWhat it means
The domain enforces p=none but subdomains only get sp=none. Attackers know this: they spoof invoices.example.com precisely because the subdomain policy is the weak one.
How to fix it
Raise sp to match your domain policy, sp=none, unless you have a specific subdomain that genuinely needs the weaker setting.
Check your own domain
This page describes the condition. To find out whether your domain has it, run the DMARC test or the full checkup, which examines every record at once.
Understand it properly
This page covers one condition. For the whole picture, The DMARC guide, from a first record to enforcement, or start at the Health Library.
Where this comes from
We judge this against RFC 9989 section 4.7. Every finding on this site cites the specification behind it so you can check the work rather than take our word for it.
Other DMARC conditions
DMARC_WEAKER_SP
Every fix on this site is yours to implement. If you would rather someone did it, I take this work directly.