UnityWebRequest "Unknown Error" from a specific computer

Hi,

We are working on two different computers with Unity 2018.3. We're testing our web service by having the Unity editor send requests to a localhost sever; however, on one of these computers Unity Editor is unable to connect properly. Debugging `UnityWebRequest.error` only says "Unknown error".

- Unity on this computer is able to properly acces an online version of the server (just by changing the URL)
- Web browsers and other apps like Postman are able to properly access the local server, so we know the server is actually working.
- If we stop the server. Unity throws a timeout error instead, so we know Unity is able to reach the server in some way.

The servers are run from Visual Studio 2017 with the Net .core SDK 2.2
On the surface, both machines look like the servers are configured in the same way, but I'm really not an expert about these; I do believe there has to be a difference between both servers, but I'm unable to figure it out.

Where should I be looking ?

I tried testing the connexion with the simplest setup I could find, an empty scene with only this script running. Tested both on 2018.3.0f2 and 2018.3.6f1

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.Networking;
5.  
6. public class Test : MonoBehaviour {
7.     static readonly string url = "https://localhost:44369/api/values";
8.     void Start()
9.     {
10.         StartCoroutine(GetText());
11.     }
12.  
13.     IEnumerator GetText()
14.     {
15.         using (UnityWebRequest request = UnityWebRequest.Get(url))
16.         {
17.             yield return request.SendWebRequest();
18.  
19.             if (request.isNetworkError) // Error
20.             {
21.                 Debug.Log(request.error);
22.             }
23.             else // Success
24.             {
25.                 Debug.Log(request.downloadHandler.text);
26.             }
27.         }
28.     }
29. }
30.  

 

Thanks for your reply.

Pure HTTP doesn't seem to work at all : On both computers, neither Unity, Postman or web browsers are able to reach through, It just hangs for a long while, then fail.
On Unity the error message is "Failed to receive data".

 

We actually never had to manipulate a UWR directly. Instead we used a plug-in SimpleHTTP which handles everything under the hood, I boiled the issue down to UWR while debugging.

In the meantime I figured how to disable SSL completely; this made http work, and https unwork completely, but at least Unity can reach through now. The local server is only for internal testing, so not having this kind of security shouldn't be an issue.

 

Hi, I am facing the same issue.
Tried using SimpleHTTP as suggested but this issue not resolved. I still see there is Unknown Error.
calling API using SimpleHTTP plug-in (not to use UWR) is what I did. Please suggest if I am missing something here.

 

I see this error everytime, Yes easily reproducible.

 

Same here, I'm using UnityWebRequest with HTTP and still the error occurs. With Postman everything is fine, so the problem is related to Unity.

 

Code (CSharp):

1.  
2.             Dictionary<string, string> header = new Dictionary<string, string>();
3.             header.Add("Content-Type", "application/json");
4.            
5.             UnityWebRequest request = new UnityWebRequest();
6.  
7.             foreach (KeyValuePair<string, string> keyValuePair in header)
8.             {
9.                 request.SetRequestHeader(keyValuePair.Key,keyValuePair.Value);
10.             }
11.  
12.             request.downloadHandler = new DownloadHandlerBuffer();
13.             request.certificateHandler = new AcceptAnyCertifacteHandler();
14.  
15.             if (string.IsNullOrEmpty(postDataTableJsonString))
16.             {
17.                 request.url = url;
18.                 request.method = "GET";
19.             }
20.             else
21.             {
22.                 byte[] bodyRaw = Encoding.GetBytes(postDataTableJsonString);
23.                 request.uploadHandler = new UploadHandlerRaw(bodyRaw);
24.                 request.url = url;
25.                 request.method = "POST";
26.             }
27.  
28.             if (Verbos)
29.                 Debug.Log($"Sending Request to url : {url} with method {request.method} and headers : \n {JsonConvert.SerializeObject(header)}  \n data: {postDataTableJsonString}");
30.  
31.  
32.             yield return request.SendWebRequest();

 

No, but I will check that and post the results here.
Thanks

 

It seems that UnityWebRequest failed to redirect to the correct endpoint. My server redirects HTTP traffic to HTTPS.
- the final request with postman is fine (don't mind 404 error code).

 

No, But the strange thing is that my HTTP proxy app cannot monitor it, I'm working on that with fiddler to see that if it can monitor that specific api.

I'm working on Windows 10 pro machine, the certificate is self-signed but trusted on my machine. In addition to this, I have used

Code (CSharp):

1. AcceptAnyCertifacteHandler

class to connect to my server. Also, I have to mention that other requests(with different api route) works and some api routes sometimes fail with "Unknown Error".

 

Certificate handler is not executed but I'm still getting the error "Unable to complete SSL connection"

 

How can I find that?

yes it works.

 

TLS 1.2

 

Currently not, But I will give you the server address when I have deployed that.

 

Having same issue, tried using Net HttpWebRequest and got more verbose error:

Code (CSharp):

1. TlsException: Handshake failed - error code: UNITYTLS_INTERNAL_ERROR, verify result: UNITYTLS_X509VERIFY_FLAG_NOT_TRUSTED

 

Having the same issue on Unity 2018.3.6.

Running my ASP.NET Core 3 API code on the localhost in Visual Studios 2019. Postman works fine to the local host running the TLS cert issued by Visual Studios for HTTPS. CORS for any origin is active on the API.

Other than having to deploy my API to a server, is there a work around? This approach would greatly slow my cycle time for development of the API and Unity Client.

string url = "https://localhost:44375/api/User/Login";
string json = @"{""username"": ""Ali"", ""password"": ""Ali@123""}";

var request = new UnityWebRequest(url, "POST");
byte[] bodyRaw = new System.Text.UTF8Encoding().GetBytes(json);
request.uploadHandler = (UploadHandler)new UploadHandlerRaw(bodyRaw);
request.downloadHandler = (DownloadHandler)new DownloadHandlerBuffer();
request.SetRequestHeader("Content-Type", "application/json");
yield return request.SendWebRequest();

 

I have switched back to

HTTP

for my local development.

 

I got it to work. Thanks for the excellent advice!

Hey Unity Admins, if you are reading this, we really need better error messaging for network errors.

VR Architect

 

I have the same problem.
In the rest API editor, requests work fine, both locally on http and on a remote server over https (TLS 1.2).
From under Android when trying to connect to a remote server https (TLS 1.2) gives Unknown Error.
This negates my efforts, I have already lost more than 1 week of time, the issue is not resolved.
Previously, I used WCF it worked fine in the editor and in Android under mono, but since that would place the apk in google play, you need to use 64bit, and this can be done on IL2CPP, and under IL2CPP WCF C library System.ServiceModel.dll is not compiled, in the end, I can use WSDL or WCF only in mono, and if mono does not support ARM64, in the end I had to go to API rest requests, rewritten the server part, and eventually under Android Unknown Error, I spent a lot of time, but there is no solution, I'm confused, a vicious circle. Please consider ARM64-enabled web services, otherwise it's just sad.

 

Rest API запросы на https (TLS 1.2) в любой сборке mono/ IL2CPP/64 bit даёт ошибку Unknown Error. Сейчас переделываю на сервере доступ по открытому каналу http, попробую подключиться без сертификата. Результат отпишу

 

Rest API requests for https (TLS 1.2) in any mono/ IL2CPP/64 bit Assembly gives an Unknown Error. Now I alter on the server access on the open channel http, I will try to be connected without the certificate. Result I will unsubscribe

 

On usual http worked perfectly. Therefore, we cannot use a certified connection. I when tested on https (TLS 1.2) I had the certificate not self-signed, and certified by the supplier, i.e. the most excellent. Anyway, the main thing though as that to work, I'll continue to use http. Thanks AminAghajoon for the hint.

 

I don't know where to write about the problem, I just found this post when I was trying to solve my problem
Your specialists can easily recreate the problem if they make an https connection on the server (perhaps a self-signed certificate)
and try to request data:
public static IEnumerator SendApi(ResponseRestApi sendInfo)
{
using (UnityWebRequest www = UnityWebRequest.Get(sendInfo.url + "?bytesInput=" + sendInfo.SendData))
{
yield return www.SendWebRequest();
while (!www.isDone) // if you need to wait for an asynchronous call
yield return true;

if (www.isNetworkError || www.isHttpError) // || www.isHttpError
{
sendInfo.result = www.error;
}
else
{
if (www.isDone)
{
string jsonResult = System.Text.Encoding.UTF8.GetString(www.downloadHandler.data);
sendInfo.result = jsonResult;
}
}
}
}

public class ResponseRestApi
{
public ObscuredString url = "";

public ObscuredString SendData = "";

public ObscuredString result = "";
}

From under the unity editor everything will work fine, but from under the android (MONO, IL2CPP (32/64bin)) there will always be an Unknown Error.
If the connection is transferred to http, then everything will work fine. But it is not a good practice to transmit data over an encrypted channel.

 

If you use the WCF (WSDL) library System.ServiceModel.dll and that work under MONO, and try to build a project under IL2CPP then at compile time will Exception and the compiler will close, ie IL2CPP is not possible to use WCF (WSDL) only rest API

 

This problem was tested on Unity 2019.1.9f1 (64-bit) and Unity 2019.2.12f1 (64-bit) Visual Studio 2017

 

I did not use a self-signed certificate, but a certified one by the supplier, i.e. fully working, even with such a certificate, the problem exists. I do not know how to use Unity bug reporter, when the application is running on an Android emulator BlueStacks, unknown Error I get from the message www.error outputting it to Text.text

 

You were right. I created two connections on the server one http, the other https. Made a test program with two buttons with the output of the result in the text field UI. And at start on BlueStacks and Nox emulators only http connection worked, for https gave an error "Unknown Error". But when I put the apk on my cell phone Xaomi Mi 9, earned both links and http and https. This is the first time when the work of the emulator and the real device are different for me.

 

Thank you for your help

 

I have the same problem.
I make a request from Unity (I tried both, with the obsolete WWW and with UnityWebRequest.Get(url) I have no return text.

I think, my code is correct:

Code (CSharp):

1. // (in a coroutine)
2. UnityWebRequest hs_get = UnityWebRequest.Get(url);
3. yield return hs_get.SendWebRequest();
4. mytext = hs_get.downloadHandler.text;

"mytext" is always empty.
But if I run the URL from a browser, the php page works and gives me the text that I need.
Is it possible that my php server does not accept requests from Unity for some reason?
PHP Version 5.4.16


[EDIT]
It doesn't depend on PHP, I also tried with a simple html page.
Like "http://www.artistic-minds.it/test1.html"
If the page is on my server it doesn't work.
It works if for test I put the "google.com" URL.

 

I tried, but nothing has changed.
This is my code.
If I try with urls like "facebook.com" or "google.com", everything works.

Code (CSharp):

1.  
2.  
3. IEnumerator GetWebData() {
4.  
5.         string url = "https://www.artistic-minds.it";
6.  
7.       // UnityWebRequest hs_get = UnityWebRequest.Get(url); //old try
8.  
9.         UnityWebRequest hs_get = new UnityWebRequest(url);
10.         hs_get.chunkedTransfer = false;
11.         hs_get.useHttpContinue = false;
12.      
13.  
14.         yield return hs_get.SendWebRequest(); // waiting for an answer
15.  
16.        /* Also tried this
17.         while (!hs_get.isDone)
18.         {
19.             yield return null;
20.         }
21.       */
22.  
23.        // yield return hs_get;   //Also tried this
24.  
25.         // string pageText = Regex.Replace(hs_get.downloadHandler.text, "<.*?>", String.Empty); //Also tried this
26.  
27.         string pageText = hs_get.downloadHandler.text;
28.  
29.         print("<color=#FFFF00>WorldLeader request URL</color> " + url);
30.         print("<color=#FFFF00>Return Text</color> " + pageText); //Always empty
31.  
32.  
33.         if (hs_get.error != null)
34.         {
35.  
36.             print("<color=#FF5500>There was an error getting the high score -</color> " + hs_get.error); // return "Unknow Error"
37.         }
38.         else
39.         {
40.             PrintOnText(pageText.Trim()); //My following function...
41.         }
42.     }

 

I "solved" it using WebClient().

Code (CSharp):

1.  
2. using (WebClient webClient = new WebClient())
3.         {
4.             webClient.Encoding = Encoding.UTF8;
5.             hs_get = webClient.DownloadString(url);
6.         }