Exoplayer - InvalidResponseCodeException (404) while file exists

Question

I am working on Exoplayer Demo to use it in my application. Everything works well except subtitles. I use Expression Encoder 4 pro to encode movies to II Smooth Streaming format. When I add English subtitle to the movie, Exoplayer shows eng-subtitles correctly but when I add Persian subtitle to the movie, Exoplayer throw an InvalidResponseCodeException. I am sure that the url is correct since I can download it by the browser.

http://www.test.com/XXX/QualityLevels(546)/Fragments(textstream_fas=0)

com.google.android.exoplayer.upstream.HttpDataSource$InvalidResponseCodeException: Response code: 404
        at com.google.android.exoplayer.upstream.DefaultHttpDataSource.open(DefaultHttpDataSource.java:204)
        at com.google.android.exoplayer.upstream.DefaultUriDataSource.open(DefaultUriDataSource.java:87)
        at com.google.android.exoplayer.chunk.ContainerMediaChunk.load(ContainerMediaChunk.java:146)
        at com.google.android.exoplayer.upstream.Loader$LoadTask.run(Loader.java:242)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:422)
        at java.util.concurrent.FutureTask.run(FutureTask.java:237)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:841)

Is there something special that I should know about it? Let me know if you need additional information.

Edit: When I open the Fragments(textstream_fas=0).* in notepad++, it shows the file is encoded in ANSI.

Thanks