babychai on "[Plugin: Visual Form Builder] VFB Pro not sending emails"

Hi Jason,

I already try that before but got error. It happen after i clicked the "Start the Wizard" button and click "Next" after i filled in my email & name. Error message pls refer below:-

Unexpected PHP messages corrupted the Ajax response:

"
\n<b>Fatal error</b>: Call to undefined function wp_send_json_error() in <b>/home/stardaz/public_html/wp-content/plugins/postman-smtp/Postman/Postman-Connectivity-Test/PostmanConnectivityTestController.php</b> on line <b>309</b>
\n"