This works with my iPhone 11 Pro Max with my thin case and a low profile glass back. However, my daughter has an iPhone 11 in a clear case with raised edges and it does NOT work. Your phone apparently needs to lay DIRECTLY on it, without an edge raising it up, for it to work.
When you initially place your phone on this charging pad, whether the case has holes in it or not, or it’s on a flat surface, the phone slides around. You may think it’s charging but it’s not. You have to keep any eye on it to make sure it’s charging.