Couldn't get response when Permanently Delete User API returns status 429

Permanently Delete User endpoint doesn't return response in my App.

Once API call hit rate limit which is 700 call per 10 mins, there is error in console.

However the App couldn't get responses nor any errors.

Does anyone has any ideas to deal with status 429 errors in Apps?

This error happens only when the app runs simultaneously by several users.

This is rare case though, I'd like to show "Too many request" error message on UI at least.

Thank you in advance.

Here is source code which has a problem.

var options = {
    url: '/api/v2/deleted_users/' + userId,
    type: 'DELETE',
    dataType: 'json',
    contentType: 'application/json',
};

try {
  return client.request(options).then(
    function (data) {
      console.error(data);
      return data;
    },
    function (error) {
      console.error(error);
      return error;
    }
  );
} catch (e) {
  console.error(e);
}