Try adding this in the Manifest, but it should work, but sometimes not known.
AddPermission (android.permission.READ_EXTERNAL_STORAGE)
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public static final String READ_EXTERNAL_STORAGE
Added in API level 16
Allows an application to read from external storage.
Any app that declares the WRITE_EXTERNAL_STORAGE permission is implicitly granted this permission.
Currently, this permission is not enforced and all apps still have access to read from external storage without this permission. That will change in a future release and apps will require this permission to read from external storage. So if your app reads from the external storage, you should add this permission to your app now to ensure that it continues to work on future versions of Android.
You can test your app with the permission enforced by either running your app on the Android Emulator when running Android 4.1 or higher, or enabling Protect USB storage under Developer options in the Settings app on a device running Android 4.1 or higher.
Note: If both your minSdkVersion and targetSdkVersion values are set to 3 or lower, the system implicitly grants your app this permission. If you don't need this permission, be sure your targetSdkVersion is 4 or higher.
Constant Value: "android.permission.READ_EXTERNAL_STORAGE"
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Jesus