Need Help with Login App Using XML/HttpURL/PHP/SQL

I am trying to create a login app using email and a password using HttpURL.
I am getting an email/password error back from the PHP I've created on the remote server.

Here is the XML that gets the email/password variables, the work well:

Code (Text):

1.  
2.            <EditText
3.                 android:id="@+id/et_email"
4.                 android:layout_width="match_parent"
5.                 android:layout_height="wrap_content"
6.                 android:hint="@string/prompt_email"
7.                 android:inputType="textEmailAddress"
8.                 android:maxLines="1"
9.                 android:singleLine="true" />
10.  
11.             <EditText
12.                 android:id="@+id/et_password"
13.                 android:layout_width="match_parent"
14.                 android:layout_height="wrap_content"
15.                 android:layout_below="@+id/email"
16.                 android:layout_marginTop= "25dp"
17.                 android:hint="@string/prompt_password"
18.                 android:inputType="textPassword"
19.                 android:maxLines="1"
20.                 android:singleLine="true" />
21.  

Here is the part of the Android Java that grabs the email/login and send the pair to PHP:


And here is the PHP, it works, I tested it on Firefox,= & Chrome, it gives me the data if it gets the right email/password, else it tells me "Wrong email/password!". But it always return the result "Wrong email/password!" to my app.

Code (Text):

1.  
2. $email = $_GET['email'];
3. $password = $_GET['password'];
4.  
5. $sql = "SELECT b.User_ID, b.User_Name, x.Unit_ID FROM Users b
6.    JOIN X_Users x ON TRIM(b.Email) = TRIM('$email') AND TRIM(b.Password) = TRIM('$password')";
7. $result = mysqli_query($conn, $sql);
8. if (mysqli_num_rows($result) > 0) {
9.    $response = array();
10.    while($row=mysqli_fetch_array($result)){
11.    array_push($response, array("User_ID"=>$row[0], "User_Name"=>$row[1], "Farm_ID"=>$row[2]));
12.    }
13.    echo json_encode(array("db_response"=>$response));
14.         echo'{"query_result":"Welcome back."}';
15. } else {
16.         echo'{"query_result":"Wrong email/password!"}';
17. };
18.  

PS 7/10/2017:
I forgot to add: JSON_STRING is null since PHP returns nothing. Worked myself into a rut again...