PHP code not executing when run thru AJAX - php

Question

I am trying to execute data if the SMS OTP is equal to Session_oTp. So, that is working fine, I am able to verify the mobile OTP is verified or not. But when trying to execute some normal query it does not run.
case "verify_otp":
$otp = $_POST['otp'];
$orderId = $_POST['orderid'];
$params = array("status" => "completed");
$body = 'orders/'.$_POST['orderid'] ;
// $woocommerce->put('orders/'.$orderId, $params);
if ($otp == $_SESSION['session_otp'] && $orderId == $_SESSION['OrderID']) {
// if ($otp == $_SESSION['session_otp']) {
echo "$params";
// $params = array("status" => "completed");
// $woocommerce->put($body, $params);
// print_r($_SESSION['OrderID']);
unset($_SESSION['session_otp']);
unset($_SESSION['OrderID']);
echo json_encode(array("type"=>"success", "message"=>"Your mobile number is verified!"));
} else {
echo json_encode(array("type"=>"error", "message"=>"Mobile number verification failed"));
}
break;
If I turn off the $params or $woocommerce query it works perfectly. Even if I try to echo a normal words, it's returning the error code.
My AJAX code is below:
$('form.otp-ver-form').on('submit', function(e){
// $(document.body).on("submit", 'form.otp-ver-form', function() {
e.preventDefault();
$(".error").html("").hide();
$(".success").html("").hide();
var $form = $( this ),
url = $form.attr( 'action' );
// var otpnumber = $form.find('input[name="otpnumber"]').val();
var otpnumber = $form.siblings('.mobileOtp').val();
var Order_ID = $form.siblings('.orderID').val();
console.log(otpnumber);
console.log(Order_ID);
var input = {
"otp" : otpnumber,
"orderid" : Order_ID,
"action" : "verify_otp"
};
if (otpnumber.length == 6 && otpnumber != null) {
$.ajax({
url : 'controller.php',
type : 'POST',
dataType: 'json',//specify data type
data : input,
success : function(response) {
console.log(response.message);
$("." + response.type).html(response.message)
$("." + response.type).show();
},
error : function() {
alert("ss");
}
});
} else {
$(".error").html('You have entered wrong OTP.')
$(".error").show();
}
});
Please let me know where is my fault or if I missing something.