smtp bounce code
501 5.1.3Bad address syntax
what to do
Suppress the address
The address is malformed. Usually a stray space, a trailing comma, or two addresses glued together by a broken export.
What the server is telling you
The server could not parse the address as an address. This is nearly always a data problem on the sending side rather than anything about the recipient.
Next steps
- →Fix the record in your list rather than suppressing it.
- →Check your CSV export: percent-encoded spaces and concatenated fields are the usual cause.
Commonly returned by: Everything
Find these before you send, not after
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