EmbedCopy the following HTML iframe code to your website:<iframe src="https://www.validify.ai/glossary/smtp-error-simple-mail-transfer-protocol/?embed=1&length=X" style="width:100%;height:300px;border:solid 1px black;" class="cm-embedded-content"></iframe>Copy to clipboardA server response code/message that indicates delivery status or why a message was rejected/temporarily deferred (e.g., 4xx temporary, 5xx permanent).
