Most common causes
- Recursive includes exceed the 10 DNS-querying-term budget
- Invalid SPF syntax
- Multiple SPF records are published
- Circular, missing or broken dependencies prevent evaluation
What to verify next
- Run the SPF Dependency Graph
- Remove stale sender authorizations
- Check for duplicate SPF TXT records
- Simulate the proposed replacement before publishing
Best diagnostic path
Live analysis
Mail Failure Doctor
Classify the complete rejection and preserve provider-specific diagnostic context.
Open analysis → Live analysisSPF Dependency Graph
Resolve recursive authorization paths, lookup pressure and the effective sender policy.
Open analysis → Live analysisEmail Infrastructure Digital Twin
Map the domain’s public mail infrastructure and provider relationships before remediation.
Open analysis →Why the exact message matters
The same status family can be triggered by different conditions, and providers frequently add diagnostic text that narrows the issue. Use the complete rejection text rather than treating the numeric code as a complete diagnosis.