The 500 SMTP error means the receiving server received a malformed command. Learn what causes this and how your email provider should fix it.
The receiving server returned a generic syntax error, meaning the SMTP command from your mail server was malformed.
These are real bounce message formats you might receive. Paste yours into the Bounce Decoder for instant analysis.
500 Syntax error, command unrecognized 500 5.5.2 Syntax error
Paste your full NDR email, SMTP error line, or mail log fragment to get an instant plain-English diagnosis.
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