I can't assign my sprite atlas to a material?

I want to use my sprite atlas as a texture for a material but I can’t add it to a material? The pack preview seems to work but only the icon of the sprite atlas remains the same. Any help would be much appreciated. (In my project setting I have: Sprite packer mode; always enabled and I have check override for IOS.)

Can you please send a screenshot fo your sprite, make sure that in the project window you have gone into the sprite and selected texture type to: 'Sprite(2D and UI). If that isn’t applied, you will not be able to set the sprite to your material.