Start here: learn email deliverability
A guided path through delivery, authentication, sending systems, audience decisions and troubleshooting.
Follow this sequence to understand the sending process and investigate your own evidence. The authentication and SMTP procedures in this path use Gmail documentation. For Yahoo-specific requirements, use the Yahoo / AOL guide hub.
1. Understand delivery stages
Separate sending, server acceptance, mailbox placement and recipient activity.
Email deliverability fundamentals →
2. Check authentication on real messages
Use Gmail’s message details to inspect SPF, DKIM and DMARC identities and results.
How to check SPF, DKIM and DMARC for Gmail →
3. Document sending infrastructure
Record the systems, domains and owners responsible for each mail stream.
Your domain architecture is part of your product infrastructure →
4. Define purpose and eligibility
Document triggers, audience rules and the conditions that stop each message.
Your email strategy should exist before your emails →
5. Maintain suppression rules
Trace unsubscribe, complaint and invalid-recipient handling through every sending workflow.
How to design email suppression rules →
6. Investigate actual SMTP failures
Preserve the full Gmail response and distinguish temporary failures from permanent rejections.
How to investigate Gmail delivery errors →
7. Respond to confirmed problems
Identify the affected stream, correct the cause and assess fresh evidence before expanding sending.
How to recover after Gmail complaints or throttling →