UnityWebRequest returning responseCode 0 and isNetworkError == true for Unity 2019

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From my Android app I execute a http PUT request with JSON:

 String fullUrl = "http://myserver.com/mycontroller/loginJson.json";
 
 UnityWebRequest www = UnityWebRequest.Put(fullUrl,json);
 
 www.SetRequestHeader("Content-Type", "application/json");
 
 yield return www.SendWebRequest();

This code works fine when building with Unity 2018.4.1f1. But if I build with Unity 2019.1.6f1 I get:

 www.error : "Unknown"
 www.responseCode: 0
 www.isNetworkError: true
 www.isHttpError: false
 www.downloadHandler.text : ""

When I run this code directly in unity, it works fine, and I have no problems communicating with the server. Only building to Android in Unity 2019.1 doesn't work. I also tried the new 2019.3.0a5, and there the Android version also works. This is quite a mystery.

Anyone have any idea what's going on?

=== UPDATE 2019-06-22 ===
I've found that it's probably not related to Unity, but to the Android SDK. If I build with API level 27 (8.1), it works fine, but with API level 29 (9.0), I get the "Unknown Error". I'll continue to look into this.
=======================

Answer 1

Best Answer

Answer by Bunny83 · Jun 22, 2019 at 02:43 PM

It's probably a security setting. Though as I said many companies try to push https as the standard in the web Many still allow http but show a warning.

Have you actually tried looking at the log? (logcat)

ps: I just had a look at the update notes

Network TLS enabled by default

If your app needs to enable cleartext for specific domains, you must explicitly set cleartextTrafficPermitted to true for those domains in your app's Network Security Configuration.

So you might need something like:

 <network-security-config>
     <domain-config cleartextTrafficPermitted="true">
         <domain includeSubdomains="true">your.domain.name.com</domain>
     </domain-config>
 </network-security-config>

Though another option is to just get a free Lets Encrypt certificate and use https. Note that Lets Encrypt certificates need to be refreshed every 3 month, however this can be automated on the server. I've done it on my raspberry pi.

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totallymorten · Jun 22, 2019 at 02:55 PM 0

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That really sounds like a plausible solution! thanks. I'm gonna look into it tomorrow and post back here! $$anonymous$$uch appreciated!

totallymorten · Jun 25, 2019 at 11:25 AM 0

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@Bunny83 I think definitely you are correct. I've been reading up on the changes in Android 9. I'm thinking either to go for your suggestion (allow http) or try to allow un-signed certificates (until I get a proper one) by using this strategy: https://answers.unity.com/questions/1482409/how-to-accept-self-signed-certificate.html

Would you like to post your answer as a "real" answer, so I can mark it "correct"?

UnityWebRequest returning responseCode 0 and isNetworkError == true for Unity 2019

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