External Storage not showing in directory selector

[Fake-MC]

I have installed the latest version of app from here on Fire tv (3rd gen) running on Android 7.
Opened the app given the storage permission.
But, in the directory selector i cannot see my external storage device to assign it to the roms folder.
I can see the primary storage but as we all know the tv storage is too low to put roms in it.
Other apps can access the external storage.
Please help.