I am getting 500 error in webhooks of Zoho CRM while trying to update in Zoho Creator

I am getting 500 error in webhooks of Zoho CRM while trying to update in Zoho Creator

Hello,

I am getting error- 500 while using webhooks from Zoho CRM to Zoho Creator for two fields only. I am using authToken, scope and zc_ownername parameter and also did setting of XmlString. I have carefully followed  instructions on  https://www.zoho.com/crm/help/automation/webhooks.html .
 Any idea what went wrong?