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5.5.0 Other or undefined protocol status

A general protocol failure without a more specific reason.

5.5.0 Other or undefined protocol status

Permanent: retrying will not help

A general protocol failure without a more specific reason.

Usual causes
  • The server did not like something in the conversation and did not say what.
What to do
  • Read the text after the code for the real reason.
  • Make sure you send through a standard mail library or an email API.

Usually the fault of: either.

Common questions.

What does 5.5.0 mean?

A general protocol failure without a more specific reason.

Will retrying fix 5.5.0?

No. It is a permanent failure, so retrying the same message will not help, and repeated attempts can hurt your sending reputation. Fix the cause first.

How do I fix 5.5.0?

Read the text after the code for the real reason. Make sure you send through a standard mail library or an email API.

Other codes: 5.1.1 · 5.1.2 · 5.1.3 · 5.1.6 · 5.2.1 · 5.2.2 · 5.2.3 · 5.3.4 · Decode a whole bounce message

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