Why can't I grant permission to my sd card so I can deal with full storage problem

[Eviltwin36]

I have a 128gb sd card 2 class.My phone is a Samsung Galaxy s5 and running on the latest system 6.01 marshmallow.
Every app that I download to sort out my storage will not grant permission so I can move apps etc to my massive mem card. It is so frustrating as I know that the space is there but my internal storage is busting!! Do you have to have a certain sd card or can I get round it somehow??

 

[matthewkuhl]

How exactly are you specifying the SD card?
Screenshot?

 

[ManiacJoe]

Most apps do not let themselves be moved to the SD card.

Some well written apps will let you move their large amounts of data to the SD card.

The SD card is best used for media files: pictures, music, videos, documents.
Your apps are best left on the internal storage.