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Fixed in 2019.3

Fixed in 2019.1, 2019.2



Found in





Issue ID




[iOS] UnityWebRequest test fails sending large data



To reproduce:
1. Open user attached project ""
2. Open "SmapleScene.unity" scene
3. Enter Play mode
4. Observe in the Game window as all tests are passing ( it should cycle 5 times )
5. Build for iOS
6. Deploy the Xcode project to an iOS device

Expected result: all the test are passing as in the Editor
Actual result: tests start to fail almost instantly

Reproduced on:
2019.1.4f1 2019.1.8f1 2019.2.0b7 2019.3.0a7

Doesn't reproduce on:
2018.4.3f1 2019.1.3f1

Devices reproduced on:
- iPhone 8 Plus iOS 12.0
- iPhone XR iOS 12.0

Device not reproduced on:
- VLNQA00263, Google Pixel 3 (Pixel 3), Android 9, CPU: Snapdragon 845, GPU: Adreno (TM) 630
- macOS 10.14 machine

- In 2019.3.0a7 on Editor tests fail on the last tests because of a timeout, changing line 32 in "NetworkTester.cs" script from WaitForSeconds(20.0f); to 30.0f all the tests pass

Comments (14)

  1. 6845e15db0d0383c2644f384bb6e1376?d=mm


    Feb 13, 2020 11:23

    If you set out to make me think today; mission accomplished! I really like your writing style and how you express your ideas. Thank you.
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  2. 6845e15db0d0383c2644f384bb6e1376?d=mm


    Feb 12, 2020 15:19

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  3. Bb67c4749eab720ebe66b6163ac29999?d=mm


    Jul 08, 2019 19:23

    Another 'ThankYou' to @RCAMDUELL. We were stuck with send failures for large data and this at least keeps things working until a permanent solution happens.

  4. D85d1d506e78ef51ec508d62048081f0?d=mm


    Jul 04, 2019 18:32

    Delete the line
    [self writeMoreBody];
    - (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didSendBodyData:...
    in Classes/Unity/
    to fix this problem.

  5. D6189aad811bf8bea3b144be8014f365?d=mm


    Jun 29, 2019 09:51

    I'm experiencing the same issue on iOs devices. However I was able to temporarily work around the problem by using System.Net.Http.HttpClient which sends large amount of data from iOs devices without any issues.

  6. 064623ceaf9f9613ab38369522fe3bc1?d=mm


    Jun 28, 2019 09:49

    Having the same problem with sending big `byte[] postData` using WWW on iOS platform. And even switching to the recommended UnityWebRequest does not help, so the problem is common to both. We too have reproduced steadily this on all released versions of 2019.1.* branch (.1.4 through .1.8) on iPad, and our customers have also the same problem on a wide variety of iOS devices (hopefully other problems are not affected).

    This critically affects our app. Since the app is cross-platform, we currently have no idea how to address this issue without using external libraries that can limit our cross-platformness. Please pay as much attention as possible to the problem. Having this still not fixed after 8 patches is unbelievable!

  7. D9b8ea2931a2e0a0d5bc42b6cb5f0fa8?d=mm


    Jun 28, 2019 07:19

    We have the same issue when sending large (6K+) base-64 encoded tokens to our server. 40% of the data is corrupted. Please fix this bug as soon as possible.

  8. 4ba73c55dadab1931d3f8388c30a9b34?d=mm


    Jun 27, 2019 06:14

    Fix it please! Thats a big problem for us

  9. 25616df50c478868a0ef9ccc02748476?d=mm


    Jun 25, 2019 16:11

    @RCAMDUELL Thank you, you're a life saver!

  10. 4f69d240746bb729eadb84aa4435a58d?d=mm


    Jun 25, 2019 16:08

    I found that the method "- (void)writeMoreBody" in Classes/Unity/ is being called on the same instance from multiple threads when the issue happens. I added @synchronized (self) {<method body>} and it seems to have worked without any obvious performance issues. I assume this method was developed to be thread safe, but something broke that.

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