The SMTP server rejected the message data sent by the client.

Remarks

The most common reasons of this error:

• The message is too large
• The server thinks the message contains SPAM or virus
• The message contains invalid headers
• The message sender and/or recipients specified in the message header differ from the actual sender/recipients, and the server does not allow this (the developer may consider adding Resent-From: header to the message specifying the actual sender e-mail address as the header value)

See Also

ErrorCodes Class | MailBee Namespace

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