Call to undefined function mysqli_stmt_get_result()

Question

I'm having a very difficult time trying to figure out why this code is returning this error:

Call to undefined function mysqli_stmt_get_result() in _____ on line 46

This code is running fine on my local machine using XAMPP, but it's not when I upload it to my webhost. On my webhost I am running PHP Version 5.5.38 and on my local machine I am running PHP Version 5.6.34. Any advice? I've tried to look at other threads here on SO to figure out what's wrong, but I haven't had much luck so far. I have the mysqlnd driver ...

The line in question is the one directly under the error checks that reads as follows:

$result = mysqli_stmt_get_result($stmt);

<?php
ini_set('display_errors', '1');error_reporting(E_ALL);

session_start();


if(isset($_POST['submit'])){
 include 'dbh.inc.php';

 $username = mysqli_real_escape_string($conn, $_POST['username']);
 $pass = mysqli_real_escape_string($conn, $_POST['password']);


 if(empty($username) || empty($pass)){
  header('Location:../login.php?login=empty');
  exit();
 } else {
  $sql = "SELECT * FROM users WHERE username = ?";
  $stmt = mysqli_stmt_init($conn);

  if (mysqli_stmt_prepare($stmt,  $sql) === false) {
      trigger_error("Prep Error: " . mysqli_error($conn));
      
  }
  if (mysqli_stmt_bind_param($stmt, "s", $username) === false) {
      trigger_error("Bind Error: " . mysqli_stmt_error($stmt));
      
  }
  if (mysqli_stmt_execute($stmt) === false) {
      trigger_error("Execute Error: " . mysqli_stmt_error($stmt));
      
  }
  $result = mysqli_stmt_get_result($stmt);
  $rows = mysqli_fetch_all($result, MYSQLI_ASSOC);

  $num_rows = count($rows);

  if($num_rows < 1){
   header('Location:../login.php?login=error');
   exit();
  } else {
   foreach ($rows as $row) {

    $hashedPwdCheck = password_verify($pass, $row['user_pass']);
    if($hashedPwdCheck == false){
     header('Location:../login.php?login=ipass');
     exit();
    } elseif ($hashedPwdCheck == true) {
     session_regenerate_id(true);

     $_SESSION['user_id'] = $row['user_id'];
     $_SESSION['username'] = $row['username'];
     $_SESSION['first_name'] = $row['user_first'];
     $_SESSION['last_name'] = $row['user_last'];
     $_SESSION['user_email'] = $row['user_email'];
     header('Location:../index.php?login=success');
     exit();
    }
   }
  }
 }

} else {
 header('Location:../index.php?login=error');
 exit();
}