PHP MYSQLI Call to a member function bind_param() : <p>my code is </p>

<pre><code>$query1 = "SELECT `user_id` FROM `it_user` WHERE (user_email_address = ? AND user_mobile_number_verified = NULL)";
          $stmt1 = $mysqli-&gt;prepare($query1);
          $stmt1-&gt;bind_param("s",$email);
          $stmt1-&gt;execute();
          if ($stmt1-&gt;affected_rows == 1) {
            //set registration flag to 1 stating that the users mobile number is already verified

            echo '&lt;meta http-equiv="refresh" content="0; URL=\'../signin/\'"/&gt;';
          }
          else
          {
            $registration_flag = 2;  
            //redirect user to error page
            //echo '&lt;meta http-equiv="refresh" content="0; URL=\'../error/\'"/&gt;'; 
          }     
</code></pre>

<p>i am getting this error :: </p>

<p>Call to a member function bind_param() on a non-object in ***** on line 62</p>

<p>where as my email variable is working corrrect and also the query.</p>
