app not run in Android 5.1

[MichaelJPCT]

i tested my app in Android 5.1 , it doesn't work.
i read the logcat i found FileNotFoundException . the file is like "/mnt/sdcard/myFolderName/myFileName.png" (pseudo names)
i don't know why, since:
1) the files are there and they can be opened by a image viewer.
2) the app runs on Android 4.2.2 and 4.4.2.

[EgonOlsen]

Haven't they changed access policies to the SD in 5? I don't know for sure, because I use to store all my static stuff in assets and the dynamic stuff in the locations that the app context provides.
But it's clearly not an engine issue... It has to be something else.

[MichaelJPCT]

you are right.
i added android.permission.WRITE_EXTERNAL_STORAGE in manifest.xml and it works now.