Fix SMTP Email Error 421 – Causes, Meaning, and Solutions (Computers - Software)

Item ID 2942496 in Category: Computers - Software

Fix SMTP Email Error 421 – Causes, Meaning, and Solutions
SMTP Email Error 421 is a temporary server-side issue indicating that the email server is currently unavailable or overloaded. The message usually reads: "421 Service not available, closing transmission channel." This error often happens when too many emails are sent at once, IP addresses are blacklisted, or the recipient's server is down. Platforms like Gmail, Outlook, and Yahoo may all experience this issue. To resolve it, reduce the sending rate, check for blacklisting, and ensure your email server has proper DNS and SPF configurations. Also, verify that your IP isn’t being flagged for spam-like activity. While servers typically retry sending automatically, persistent errors require checking logs and contacting your hosting provider. Implementing proper throttling, monitoring tools, and security protocols helps prevent SMTP 421 errors from recurring and ensures smooth email delivery.
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Target State: Illinois Target City : Chicago Last Update : May 01, 2025 7:41 AM Number of Views: 53	Item Owner : RI7W81f6UJYilY4k Contact Email: Send email to item owner Contact Phone: +1 08144488848

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2025-07-07 (0.386 sec)