Why is my screen separator machine losing suction?

As the title suggests, my screen separator machine is losing suction while trying to separate the LCD from the glass. I’m new to this so I do not believe it is the machine itself as I just got it. When I start out with the screen, everything is fine, however, once the wire has gotten maybe 1/4 of an inch under the glass, it becomes very hard to keep the screen in place.

Any suggestions?