Hello @nilesh0308
That issue is still coming when user is cancelling transaction.
See the details of error page:
Unfortunately your order cannot be processed as the originating bank/merchant has declined your transaction. Please attempt your purchase again.
Warning: call_user_func_array() expects parameter 1 to be a valid callback, class ‘WC_nilesh_Ccave’ does not have a method ‘thankyou_page’ in /home/gillthal/public_html/wp-includes/plugin.php on line 525
Kindly suggest fix.
Thanks