message

A human-readable message providing more details about the error. For card errors (type == ApiErrorType.CARD_ERROR), these messages can be shown to your users.

When a LocaleConfig is set, this message may be returned in a non-English locale. Inspect localizationResult to determine the locale of the message. Avoid relying on message content for application logic, since the content may change.

If the server does not provide a message, this defaults to "Unknown API error" (English).