Accessing a pdf from internal storage throws file not found exception

Am trying a populate a pdf which is stored in internal storage is throwing FileNotFoundException.

    File file1 = new File(Environment.getExternalStorageDirectory()+"/pdf/Read.pdf");
    pdfView.fromFile(file1)
            .defaultPage(1)
            .onPageChange(this)
            .swipeVertical(true)
            .showMinimap(false)
            .load();

But when I manually check the directory, I could see that file exist. Or some times its giving me com.shockwave.pdfium.PdfOpenException: Open document failed in my log

[shyamsam]

@barteksc thanks for you reply,

am still facing the same issue as @ENOZA has mentioned in earlier comments. I have given the permission in the manifest.

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.INTERNET" />

Am downloading the file from a remote server to a folder in phone storage. If I go to that particular directory I could see that file exists there and am able to open that file with other pdf viewers. The error an getting is when an populating the pdf. The log is shown below:

com.shockwave.pdfium.PdfOpenException: Open document failed
at com.shockwave.pdfium.PdfiumCore.newDocument(PdfiumCore.java:72)
at com.github.barteksc.pdfviewer.DecodingAsyncTask.doInBackground(DecodingAsyncTask.java:61)
at    com.github.barteksc.pdfviewer.DecodingAsyncTask.doInBackground(DecodingAsyncTask.java:32)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:841)

[kondasusmithareddy]

Pdf is not working in Kitkat version.When I Click on link,It Displaying Blank Page in My Emulator,Can u help me Please