Troubleshooting
Practical troubleshooting guides for email authentication and deliverability issues. Diagnose SPF, DKIM, DMARC, DNS, and mail delivery failures.
Articles 3
DKIM Signature Verification Failed: Causes and Fixes
iagnose DKIM verification failures, from missing selector records and revoked keys to body hash mismatches, relay modifications and key rotation.
DMARC Alignment Failed: Why SPF and DKIM Pass but DMARC Fails
SPF and DKIM can pass while DMARC fails. Learn how domain alignment works, identify the cause, and fix common authentication failures.
SPF PermError: How to Fix the 10 DNS Lookup Limit
An SPF record can exceed the DNS lookup limit even with only a few includes. Trace nested records, find the real cause of PermError, and fix it safely.