Codeigniter RestFull Api Call Show Error on Postman

Its Baseurl of api call http://localhost/data_model/users/login when i run this in postman or browser its show me the error. My all links after data_model like data_model/a or data_model/b that are created in folders show me same error.

Error: {"status":false,"message":"Invalid Request","data":[],"auth_code":"100100"}

`

public function login() { $input = $this->validate_login();

    $user = $this->Users_model->login($input);
    if ($user) {
        if ($user['status'] == 1)
            return_data(false, 'Your Account Disabled', json_decode("{}"));
        else if ($user['status'] == 1)
            return_data(false, 'Account Deleted', json_decode("{}"));
        else {
            return_data(true, 'User authentication successful.', $user);
        }
    }
    return_data(false, 'Authentication Failed', json_decode("{}"));
}

`