MU
MUHAMMAD USMANSOFTWARE ENGINEER • FLUTTER & AI
DIAGNOSTIC UTILITY // SOCKET & TLS

SMTP & Mail Server Diagnostic Tester

Test live SMTP mail server connection handshakes, verify SSL/TLS certificates, validate credentials, probe DNS MX routing, and troubleshoot delivery issues in real time.

QUICK PRESETS (1-CLICK CONFIGURATION):
CONNECTION PARAMETERS
AUTHENTICATION (OPTIONAL)NEVER LOGGED
SMTP_DIAGNOSTIC_SOCKET // smtp.gmail.com:587
[Ready] Awaiting connection diagnostics initiation...
SMTP RESPONSE CODE CHEATSHEET
220 / 250 OK

Service ready & command completed successfully. Mail server is operational.

421 Service Unavailable

Temporary rate limit, IP throttling, or server maintenance. Retry after delay.

535 Authentication Failed

Invalid credentials or 2FA active. Generate an App Password in provider settings.

550 / 554 Relay Denied

Recipient rejected or sender domain unverified. Check SPF/DKIM and sender records.