How to fix smtplib 535 authentication failed

If you have no SMTP credentials, send over HTTP instead. The same message shape works with no auth.

Run it

curl -s -X POST https://api.model.tools/v1/send -H 'Content-Type: application/json' -d '{"to":"u@example.com","subject":"Alert","body":"done"}'

Response

{"ok":true,"status":"delivered","relay_provider":"agent-relay-v1"}