Start with the symptom that matches your problem. Check the message in Email Logs when a send fails; its status and error message show what the provider reported.
Sending problems
- An email isn’t sending — check its log and the connection it should use.
- Connection and authentication errors — fix rejected credentials, OAuth access, or a connection timeout.
- A failed email isn’t being retried — check retry settings and the failed message’s attempts.
- A From address is already in use — see why each From address belongs to one connection.
A test says sent, but nothing arrived
Test email sent successfully! means the send transport reported success; it does not confirm delivery to the inbox. Check why the email did not arrive, or use the interactive checks one question at a time.
Other problems
If BooleanSMTP shows Page not found, read the message on screen and click Go to Overview. The Migration screen has no sidebar entry: press ⌘K (Mac) or Ctrl K (Windows and Linux), type Migration, and press Enter.
For deeper diagnosis, see the available diagnostic tools.
Diagnostic tools
- Log mailer resolution to PHP error log (Settings → Logging & Retention) writes one JSON line per email showing which connection and transport were chosen.
- SMTP Debug Level, on an SMTP connection’s edit form, captures the raw SMTP conversation for that connection’s sends.
- Test Email Activity Console (Settings → Testing & Content) shows the SMTP handshake on the Test Email page for a manual test send.
Turn diagnostic logging back off when you’re done so the server error log does not keep receiving a line for every email.