Email Error Troubleshooting

Step-by-step fixes for common email rejection codes from Gmail, Outlook, and Yahoo.

550 5.7.26 — Gmail DMARC Rejection

Why Gmail rejects unauthenticated mail and how to restore DMARC alignment quickly.

Fix SPF PermError by reducing includes, flattening safely, and staying under the 10-lookup limit.

Resolve Microsoft 365 authentication failures that trigger 550 5.7.515 rejections.

Understand SPF/DKIM alignment rules and fix misaligned senders causing DMARC fails.

Troubleshoot Microsoft SPF policy violations and repair SPF authorization for legitimate senders.

Diagnose and fix DKIM body hash mismatches caused by message modifications in transit.

Address generic DMARC policy rejections and identify which authentication signal is failing.

Fix Yahoo DMARC enforcement errors by aligning third-party senders and authentication records.