How to make an Ajax call to action method in different controller - asp.net

Question

I have following scenario.
Route Config:
routes.MapRoute(
name: "SellerRegistration",
url: "Registration/{action}/{id}",
defaults: new { controller = "SellerRegistration", action = "Seller", id = UrlParameter.Optional, area = "" },
namespaces: new[] { "MyCompany.Controllers" }
);
So when the url is www.example.com/Registration/Seller, the above route will match and displaying the view without any issues.
class SellerRegistration
{
public ActionResult Seller()
{
return View("Seller");
}
[AjaxOnly]
public bool ValidateUserEmail(string email)
{
return _userService.ValidateUserEmail(email);
}
}
Inside my view Seller.cshtml, I'm trying to make an ajax call to the method ValidateUserEmail().
I'm making ajax call as below:
$.ajax({
type: "POST",
url: rootUrl + "/SellerRegistration/ValidateUserEmail",
cache: false,
async: false,
data: { email: $("#Email").val() },
success: function (data) {
if (data === 'True') {
//redirect to login page
window.location.href = newUrl;
} else {
$("#otherDetails").show();
$("#emailValidation").hide();
$("#submitCompleteFormDiv").show();
}
},
error: function (data, jqXhr) {
console.log(jqXhr.status);
}
});
I have also tried generating url as below in the above ajax method.
url: '#Url.Action("SellerRegistration", "ValidateUserEmail")'
But I'm getting
401 - Unauthorised error.
I'm guessing that I'm not able to make ajax call because of the routing I configured. But, that routing is required to meet other scenarios in the application.
When ajax call is made, the url format is like www.example.com/Registration/Seller
So browser initiates an ajax call to the ValidateUserEmail method inside the controller SellerRegistration from www.example.com/Registration/Seller.
Because there is no real controller named Registration, when the ajax call is made to ValidateUserEmail() inside SellerRegistration controller, I'm getting 401 Unauthorized error.
Can someone please suggest if there is any technique or workaround to make it possible.
Thank you.