What Happens If Email Authentication Fails?
Understanding authentication failure consequences and how to fix them
Table of Contents
What Happens If Email Authentication Fails?
When email authentication fails (SPF, DKIM, or DMARC), several serious consequences occur: emails may be filtered as spam (higher spam scores), emails may be rejected or blocked by ISPs, deliverability rates decrease significantly, sender reputation is negatively affected, and emails are more likely to be quarantined or rejected.
Authentication failures significantly impact email deliverability and can cause legitimate emails to be filtered or blocked. Understanding failure consequences helps prioritize authentication setup and monitoring.
Verify your authentication using our email authentication checker to identify and fix authentication failures before they impact deliverability.
SPF Failures
What Causes SPF Failures?
SPF failures occur when the sending IP address is not authorized in the domain's SPF record.
Common SPF Failure Causes
- Missing SPF records
- Sending from unauthorized IPs
- Incorrect SPF record configuration
- Missing include: statements for third-party services
- SPF record syntax errors
SPF Failure Consequences
SPF failures increase spam scores, reduce deliverability, and may cause emails to be filtered or rejected, especially with strict DMARC policies.
Fixing SPF Failures
Fix SPF failures by updating SPF records to include all authorized sending IPs and services. Verify with SPF lookup.
DKIM Failures
What Causes DKIM Failures?
DKIM failures occur when DKIM signatures cannot be verified, typically due to missing or incorrect DKIM records.
Common DKIM Failure Causes
- Missing DKIM signatures
- Incorrect DKIM record configuration
- Key mismatches (wrong public key)
- Signature tampering
- Missing or incorrect selector configuration
DKIM Failure Consequences
DKIM failures increase spam scores, reduce deliverability, and may cause emails to be filtered, especially if SPF also fails.
Fixing DKIM Failures
Fix DKIM failures by verifying DKIM records are published correctly and mail servers are configured to sign emails. Verify with DKIM lookup.
DMARC Failures
What Causes DMARC Failures?
DMARC failures occur when both SPF and DKIM fail, or when they don't align with the From domain according to DMARC policy.
Common DMARC Failure Causes
- Both SPF and DKIM fail
- SPF or DKIM fails alignment with From domain
- Missing DMARC records
- Incorrect DMARC policy configuration
- Alignment mode mismatches
DMARC Failure Consequences
DMARC failures result in policy enforcement: none (accept), quarantine (send to spam), or reject (block). Stricter policies cause more severe consequences.
Fixing DMARC Failures
Fix DMARC failures by ensuring SPF and DKIM both pass and align. Start with 'none' policy for monitoring, then progress to stricter policies.
Failure Consequences
1. Spam Filtering
Authentication failures significantly increase spam scores. Emails without authentication are more likely to be filtered as spam. Test with our SpamAssassin test.
2. Email Rejection
ISPs may reject or block emails that fail authentication, especially with strict DMARC reject policies.
3. Deliverability Reduction
Authentication failures significantly reduce deliverability rates, impacting inbox placement and email campaign performance.
4. Reputation Damage
Consistent authentication failures damage sender reputation, affecting long-term deliverability across all campaigns.
5. Quarantine
Emails may be quarantined (sent to spam folders) when DMARC policies are set to quarantine for failures.
6. Loss of Trust
ISPs lose trust in senders who consistently fail authentication, applying stricter filtering and blocking.
How to Fix Authentication Failures
1. Verify Current Status
Use our comprehensive authentication checker to identify which protocols are failing.
2. Fix SPF Issues
Update SPF records to include all authorized sending IPs. Verify with SPF lookup.
3. Fix DKIM Issues
Verify DKIM records are published correctly and mail servers are signing emails. Verify with DKIM lookup.
4. Configure DMARC
Set up DMARC policies starting with 'none' for monitoring. Verify with DMARC lookup.
5. Test Regularly
Test authentication regularly to ensure all protocols continue to work correctly after changes.
6. Monitor Results
Monitor authentication results in email headers and DMARC reports to identify issues early.
