Azure http-put UnityWebRequest on android

Question

I'm trying to upload a video to a private Azure blob. The UnityWebRequest works perfectly on PC, but once it's built on an Android device it keeps returning a 403 error.

For debugging I tried to use the normal HttpWebRequest on the android device, with the same settings, which works fine. It's not an option to switch over to HttpWebRequest.

I'm wondering whether the HttpWebRequest has some default options that the UnityWebRequest doesn't, or if perhaps anyone knows of other issues?

HttpWebRequest: Works on both devices

I can provide code if necessary.

[Update]

public IEnumerator PutBlob(string filePath, string blockBlobReference)
{
    String httpMethod = "PUT";

    Byte[] blobContent = File.ReadAllBytes(filePath);

    Int32 blobLength = blobContent.Length;

    const String blobType = "BlockBlob";

    String urlPath = String.Format("{0}/{1}", AzureStorageConstants.container, blockBlobReference);
    String msVersion = "2009-09-19";
    //String msVersion = "2015-02-21";
    String dateInRfc1123Format = DateTime.UtcNow.AddHours(1).ToString("R", CultureInfo.InvariantCulture);

    String canonicalizedHeaders = String.Format("x-ms-blob-type:{0}\nx-ms-date:{1}\nx-ms-version:{2}", blobType, dateInRfc1123Format, msVersion);
    String canonicalizedResource = String.Format("/{0}/{1}", AzureStorageConstants.Account, urlPath);
    String stringToSign = String.Format("{0}\n\n\n{1}\n\n\n\n\n\n\n\n\n{2}\n{3}", httpMethod, blobLength, canonicalizedHeaders, canonicalizedResource);
    String authorizationHeader = CreateAuthorizationHeader(stringToSign);

    Uri uri = new Uri(AzureStorageConstants.BlobEndPoint + urlPath);
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
    request.Method = httpMethod;
    request.Headers.Add("x-ms-blob-type", blobType);
    request.Headers.Add("x-ms-date", dateInRfc1123Format);
    request.Headers.Add("x-ms-version", msVersion);
    request.Headers.Add("Authorization", authorizationHeader);
    request.ContentLength = blobLength;

    ServicePointManager.ServerCertificateValidationCallback = MyRemoteCertificateValidationCallback;

    using (Stream requestStream = request.GetRequestStream())
    {
        requestStream.Write(blobContent, 0, blobLength);
        yield return requestStream;
    }

    using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
    {
        String ETag = response.Headers["ETag"];
    }
}

UnityWebRequest: Works on computer, but not on android

public IEnumerator PutBlob(string filePath, string blockBlobReference)
{
    String httpMethod = "PUT";

    Byte[] blobContent = File.ReadAllBytes(filePath);

    Int32 blobLength = blobContent.Length;

    const String blobType = "BlockBlob";

    String urlPath = String.Format("{0}/{1}", AzureStorageConstants.container, blockBlobReference);
    String msVersion = "2009-09-19";
    //String msVersion = "2015-02-21";
    String dateInRfc1123Format = DateTime.UtcNow.AddHours(1).ToString("R", CultureInfo.InvariantCulture);

    String canonicalizedHeaders = String.Format("x-ms-blob-type:{0}\nx-ms-date:{1}\nx-ms-version:{2}", blobType, dateInRfc1123Format, msVersion);
    String canonicalizedResource = String.Format("/{0}/{1}", AzureStorageConstants.Account, urlPath);
    String stringToSign = String.Format("{0}\n\n\n{1}\n\n\n\n\n\n\n\n\n{2}\n{3}", httpMethod, blobLength, canonicalizedHeaders, canonicalizedResource);
    String authorizationHeader = CreateAuthorizationHeader(stringToSign);

    Uri uri = new Uri(AzureStorageConstants.BlobEndPoint + urlPath);

    ServicePointManager.ServerCertificateValidationCallback = MyRemoteCertificateValidationCallback;

    using (UnityWebRequest webRequest = new UnityWebRequest())
    {
        webRequest.SetRequestHeader("x-ms-blob-type", blobType);
        webRequest.SetRequestHeader("x-ms-date", dateInRfc1123Format);
        webRequest.SetRequestHeader("x-ms-version", msVersion);
        webRequest.SetRequestHeader("Authorization", authorizationHeader);

        UploadHandler uploadHandler = new UploadHandlerRaw(blobContent);
        webRequest.uploadHandler = uploadHandler;
        uploadHandler.contentType =
        webRequest.url = uri.ToString();
        webRequest.method = httpMethod;
        webRequest.Send();


        while (!webRequest.isDone)
        {
            ProgressBar = webRequest.uploadProgress;
            yield return null;
        }
    }
}