SMTP Error 501

What causes this error and solutions

SuprSend provides APIs and components for you to create notification workflows that drive collaboration & actions from your users - ensuring higher product adoption.

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SMTP Error 501 occurs when there is a syntax error in parameters or arguments of the email message or SMTP commands. This error indicates a failure in processing the email due to incorrect formatting.

How to fix SMTP Error 501?

To resolve SMTP Error 501, follow these steps:

  • Review the email message: Carefully review the email message content, including headers, subject lines, and recipient addresses, to ensure they adhere to standard email format requirements.
  • Check recipient addresses: Verify that the recipient's email address is spelled correctly and formatted properly.
  • Address syntax errors: Correct any syntax errors in the email message or SMTP commands. Ensure that commas, periods, and other punctuation are correctly placed.
  • Avoid suspicious content: If you suspect spam or security filters are causing the SMTP error 501, review the email's content for potentially problematic elements, such as suspicious links or attachments.

SMTP Error 501 Examples

  • Case 1: "501 Syntax error in parameters or arguments."
  • Case 2: "501 5.1.7 Invalid address in 'RCPT TO' command: <recipient@example..com>"
  • Case 3: "501 5.5.4 Invalid header format in email message."
  • Case 4: "501 5.7.1 Message content flagged as spam. Refused delivery."

Say Goodbye to all SMTP Errors in Development

SuprSend eliminates the need to build and configure email servers from scratch, ensuring you steer clear of SMTP errors. Here's how SuprSend would work for your application, building a reliable notification system.
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Written by:
Sanjeev Kumar
Engineering, SuprSend

Say Goodbye to all SMTP Errors in Development

SuprSend eliminates the need to build and configure email servers from scratch, ensuring you steer clear of SMTP errors. Here's how SuprSend would work for your application, building a reliable notification system.
Dashboard mockup

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