How email delivery works after you click Send
1. The campaign enters the queue
SynerMail prepares recipients and background workers dispatch messages. Watch Overview for changes from Queuing to Sending and Done. If progress stops, check queue health and the sending provider.
2. The sender looks up a mail server
The sender uses DNS to route mail for the recipient domain. Inspect the bounce or provider diagnostic when lookup fails. Some domains can receive mail without an explicit MX record.
3. The servers negotiate SMTP
The sending server connects, identifies the envelope sender and recipient, and transmits the message. A temporary 4xx reply may lead to a retry. A permanent 5xx reply requires inspecting the response and correcting the underlying issue.
4. TLS protects the connection
SMTP can upgrade to encryption with STARTTLS during the connection, before transferring the message. Check the sending provider logs or SMTP configuration when diagnosing TLS failures.
5. The receiving server evaluates authentication and placement
SPF checks whether the sending IP is authorized for the SMTP identity. DKIM verifies a domain signature. DMARC requires alignment of at least one passing SPF or DKIM identity with the visible From domain. See DNS configuration.
Find the failure
- Queue stalled: check workers, pending jobs, and provider connectivity.
- Hard bounces on a new import: inspect recipient addresses and SMTP responses.
- Temporary failures at one provider: look for throttling or temporary provider errors.
- Delivered but missing: check spam, quarantine, inbox rules, and recipient-side logs. Delivered means the receiving server accepted the message.
See campaign reporting for the logs and metrics available after a send.