Edit Canvas

I was working on notewise and writing in a canvas when all of a sudden, i can’t do that in any of my already existing canvas. When i try to click on the eye symbol, to have the tools pop up so i can write, edit, etc. A text pops up that says i can’t edit the canvas, although i was just working on it a couple of minutes before that. I tried to edit other canvas but the same problem arises.