If I choose a non avaible item with a red background, and I take the item in the 2x2 or 3x3 crafting table, and put it in one of the other places in the table, it turns to avaible with grey background, and than I can have it.
In the example: I choose Slimeball, take the Slime Block, put it down one, and than I can take it.

Tablet, Alcatel One touch Pixi, Android 5.1.1, MC PE v1.2.6 (updated 7.12.2017.) Survival mode