Nusoap不支持PHP password_hash函数?

我正在为.net的登录过程编写一个简单的web服务。我在服务器端使用nusoap php库。在服务器端,我正在对给定的密码进行哈希运算,并在数据库中查询它,以检查是否存在这样的哈希密码。但是在.net中,我得到了一个错误,即响应是text/html格式,而它在等待text/xml格式。错误是password_hash函数找不到,但这是php的内置函数。我在单独的.php文件中检查了这些函数,并且它在加密和解密(password_verify)时都能正常工作。那么,在这种情况下,我哪里出错了?

这是我的代码;

function systemLogin($mycomplexlogin)
{
    $result=NULL;
    $conn=openConnection();
    // Check connection
    if ($conn->connect_error)
    {
        //return("Connection failed: " . $conn->connect_error);
        return $result;
    } 
    $EnterpriseId=mysqli_real_escape_string($conn,$mycomplexlogin["EnterpriseId"]);
    $UserName=mysqli_real_escape_string($conn,$mycomplexlogin["UserName"]);
    $Password=$mycomplexlogin["Password"];
    $cost=10;
    $hash="";
    $hash=password_hash($Password, PASSWORD_BCRYPT, ["cost" => $cost]);
    /* create a prepared statement */
    $stmt =  $conn->stmt_init();
    // prepare and bind
    if($stmt = $conn->prepare("SELECT * FROM mydatabase.USERS WHERE BINARY  username=?"))
    {
        $stmt->bind_param("s", $UserName);
        // execute query
        $stmt->execute();
        /* bind result variables */
        $stmt->bind_result($resultId,$resultLastName,$resultFirstName,$resultAddress,$resultPosition,$resultManager,$resultUserName,$resultPass);
        /* fetch value */
        if($stmt->fetch()) 
        {
            if(password_verify($Password,$hash))
            {
            //date("Y-m-d H:i:s");
            $token=date("Y-m-d H:i:s");
            $result= array(
            'Id' => $resultId,
            'LastName'=>$resultLastName,
            'FirstName' => $resultFirstName,
            'Address'=>$resultAddress,
            'Position'=>$resultPosition,
            'Manager'=>$resultManager,
            'Password' => $resultPass,
            'UserName' => $resultUserName,
            'Token' => $token
            );
            }
        }
        // close statement
        $stmt->close();
    }
    mysqli_close($conn);
    return $result;
}