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What Does the "440 Posting Failed: Header Not in Internet Syntax" Error Mean?
When you attempt to post to a Usenet newsgroup and receive the error message:
440 Posting Failed: Header Not in Internet Syntax
It means your newsreader is sending an article with incorrectly formatted headers.
Usenet headers must follow standard Internet formatting protocols. If even one required header—such as From, Subject, or Newsgroups—is malformed or missing, the post will be rejected by the server.
This error is typically caused by one of the following:
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A missing or improperly formatted From address (e.g., missing domain)
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An empty Subject line
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A Newsgroups header that doesn't contain a valid group
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Improper line breaks or special characters in the header fields
How to Resolve the Issue
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Review your header fields: Make sure the From field includes a properly formatted email address (example:
[email protected]). -
Check for typos: Incorrect punctuation or formatting in the Subject or Newsgroups fields can trigger this error.
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Verify your newsreader settings: Some newsreaders allow you to set a default From or Reply-To address. Double-check that these are correctly formatted.
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Contact your newsreader’s support: If you're unsure where to update these settings, your newsreader’s help documentation may provide guidance.
If the error persists after reviewing your settings, try posting to a different newsgroup to rule out group-specific issues.
