Why does the same php UnityWebRequest does not work on plesk server but works on my localhost?

Question

I am developing an app in unity and I am currently coding the login functionality. I have also created a database for my users in plesk. I have been updating and inserting new users from my apache local host normally until now. I copied my php files into my hosting server and now all the responses I get are null and the response error is "Unknown error".

I tried making calls directly from my browser with @_GET and they work as intended. I also called the plesk support team, they said it should work and I could try checking the php version the server is using and match it with mine. Still nothing.

php code

 if(@$_POST['cmd'] == 'login_mobile'){

    $username_input = $_POST["username"];
    $password_input = $_POST["password"];

    //to prevent mysql injections
    $username = stripcslashes($username_input);
    $password = stripcslashes($password_input);

    $query = "SELECT * FROM users WHERE first_name='$username'";
    $response = mysqli_query($dbc, $query);

    //check password
    $row = mysqli_fetch_array($response);
    if( $row['first_name'] == $username && $row['phone'] == $password ){
        $user_id = $row['id'];

        $query2 = "SELECT * FROM conversation WHERE creator_id='$user_id'";
        $response2 = mysqli_query($dbc, $query2);
        $row2 = mysqli_fetch_array($response2);

        $query_set_active = "UPDATE users SET is_active = 1 WHERE id='$user_id'";
        $response_active = mysqli_query($dbc, $query_set_active);

        echo 'Login success,' . $row['id'];
    }
    else{   
        echo 'fail';
    }   
    die;
}

unity code c# (request)

IEnumerator Connection(string first_name, string password)
{
    WWWForm conn = new WWWForm();
    conn.AddField("cmd", "login_mobile");
    conn.AddField("username", first_name);
    conn.AddField("password", password);

    UnityWebRequest response = UnityWebRequest.Post("https://www.katiawashere.gr/qr/func/get_user_info.php", conn);

    yield return response.SendWebRequest();

    if (String.IsNullOrEmpty(response.error))
    {
        if (response.downloadHandler.text.Contains("Login success"))
        {
            serverResponseUi.text = "Login successfull";

            string[] splitedResponse = response.downloadHandler.text.Split(new string[] { "," }, StringSplitOptions.None);

            //Set the user id
            int.TryParse(splitedResponse[1], out StaticHolder.userid);
            SceneManager.LoadScene("Chatter");
        }
        else
        {
            serverResponseUi.text = "Could not Login";
        }
    }
    else
    {
        serverResponseUi.text = "Cannot connect to server: " + response.error;
    }
}

Here is the link that actually responds https://www.katiawashere.gr/qr/func/get_user_info.php?cmd=login_mobile&username=User&password=696969 . The request however returns null and the request error is "Unknown error". I feel like searching a needle in a haystack, any feedback is appreaciated.

Answer 1

When using https you have to implement a UnityWebRequest-certificateHandler eg example from Unity

// Based on https://www.owasp.org/index.php/Certificate_and_Public_Key_Pinning#.Net
class AcceptAllCertificatesSignedWithASpecificKeyPublicKey : CertificateHandler
{
    // Encoded RSAPublicKey
    private static string PUB_KEY = "30818902818100C4A06B7B52F8D17DC1CCB47362" +
        "C64AB799AAE19E245A7559E9CEEC7D8AA4DF07CB0B21FDFD763C63A313A668FE9D764E" +
        "D913C51A676788DB62AF624F422C2F112C1316922AA5D37823CD9F43D1FC54513D14B2" +
        "9E36991F08A042C42EAAEEE5FE8E2CB10167174A359CEBF6FACC2C9CA933AD403137EE" +
        "2C3F4CBED9460129C72B0203010001";

    protected override bool ValidateCertificate(byte[] certificateData)
    {
        X509Certificate2 certificate = new X509Certificate2(certificateData);
        string pk = certificate.GetPublicKeyString();
        if (pk.Equals(PUB_KEY))
            return true;

        // Bad dog
        return false;
    }
}

or alternatively (unsecure to simply accept all ssl certificates)

class AcceptAllCertificates : CertificateHandler
{
    protected override bool ValidateCertificate(byte[] certificateData)
    {
        return true;
    }
}

and use it in your request like

UnityWebRequest response = UnityWebRequest.Post("https://www.katiawashere.gr/qr/func/get_user_info.php", conn);

response.certificateHandler = new AcceptAllCertificatesSignedWithASpecificKeyPublicKey();

//or
response.certificateHandler = new AcceptAllCertificates();

yield return response.SendWebRequest();