553 Requested action not taken: mailbox name not allowed

An address in the message is not in a form the server accepts. Often it is the sender address.

553 Requested action not taken: mailbox name not allowed

Permanent: retrying will not help

An address in the message is not in a form the server accepts. Often it is the sender address.

Usual causes

The From address is not allowed to send through this server.
An address is written wrongly, such as a missing domain.
The server requires the sender address to match the account you logged in with.

What to do

Send from an address you are allowed to use with this server.
Check every address for typos.

Usually the fault of: sender.

Common questions.

What does 553 mean?

An address in the message is not in a form the server accepts. Often it is the sender address.

Will retrying fix 553?

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 553?

Send from an address you are allowed to use with this server. Check every address for typos.

Other codes: 250 · 421 · 450 · 451 · 452 · 500 · 501 · 503 · Decode a whole bounce message

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