PRACTICAL RESOURCES

Error codes: SMTP

Find SMTP error codes, explanations and diagnostic resources. Open an English reference page to check the message and the relevant next steps.

6resources available

Resource 535 5.7.139 — SMTP AUTH deactivated Open → Resource 535 5.7.3 — SMTP authentication failed Open → Resource 550 5.1.1 — Unknown recipient Open → Resource 55057.1 — Unauthorised shipment Open → Resource 550 5.7.1 — Sender mismatch Open → Resource 554 5.7.1 — Message rejected as spam Open →

Support the development of BAOI Hosting, domains and new IT resources.

❤️ Support BAOI