As mentioned debug tips by @revant_one , i was able to solve it by following the below steps
- Ignore on webhook save Error related to Delivery URL
- Enabled word press debug true
- Wait for few min for the error log to refresh and check the error log in Woocommerce >Status > Log > Select “webhook delivery - related log” and if you scroll down you will able to find the exact frappe error , in my case the default customer_group and territory was not set in the “Selling Settings” in ERPNext.
Thanks a lot !