Record the message type, intended recipient, sender address and exact test time. Check whether the problem affects password resets, one form, commerce notifications or every outgoing message. Use controlled test data and avoid sending repeated messages to real customers while diagnosing.

Check the recipient's spam folder and whether the address is correct, but do not stop there if messages consistently fail.

1. Confirm that the application generated the notification and that its own setting is enabled.
2. Identify whether WordPress uses the server's mail path, an SMTP plugin or an external email API.
3. Review the relevant plugin or provider logs for acceptance, rejection or authentication errors.
4. Check sender-domain authentication and the permitted sender identity for that transport.
5. Review bounce or delivery events at the sending provider when the message was accepted but not delivered.

For a contact form, use a sender address belonging to an authorised domain and put the visitor's address in Reply-To where the form supports it. Pretending to send directly from an arbitrary visitor's domain can fail authentication checks.

Configure SMTP or API credentials through the approved integration and keep them out of public logs. Use the provider's required encryption and authentication settings rather than disabling them to bypass an error.

Send one controlled notification to a mailbox you can inspect. Confirm both the provider's result and actual arrival, then review the message headers if authentication or alignment is in question.

Test the original workflow after a standalone transport test. A successful test-email button does not prove a particular form or order event triggers the notification correctly.

Provide the domain, message type, time, sender and recipient domains, and a sanitised error or message identifier. Do not expose mailbox passwords, API keys or the full content of private customer messages.

If only one recipient provider rejects mail, collect its bounce reason rather than changing every WordPress plugin. If mail stopped after a fatal error, the normal mail plugin may not have loaded for the recovery notification. Keep generation and transport evidence separate so retries do not create duplicate customer messages once the underlying queue resumes.

• Troubleshooting missing WooCommerce order emails
• Sharing a sanitised WordPress error log with support
• Setting up subdomains and website redirects
• Diagnosing a slow WordPress dashboard

• WordPress developer documentation
• WordPress documentation
• cPanel email deliverability