Excellent print quality, awful adhesion

The print quality on these is outstanding, like any other product I've gotten from sticker mule, (even with my crummy artwork) But the cling adhesion is awful. I also assumed they clinged on the artwork side, but they don't. As in, inside of a window. They sit like a sticker that doesn't adhere to anything. I've tried them on a dozen different surfaces and different windows and they just don't cling.