Why does my Samsung 4 keep saying, currently unable to download?

[AC Question]

My Samsung Galaxy 4 is always saying, currently unable to download. Please try again later. Can you tell me why?

 

[Keithtrader]

Mine too. It's only started happening since the marshmallow software update. I'm also getting a notification saying I'm in game mode and messenger has stopped working as well

 

[Cory West]

Same here since the Marshmallow update on Galaxy S5. I'm going through all my SMS messages and deleting the voicemails that ask if you want to download them, see if that works.