This problem cannot he too hard to remedy. You don't say what kind of fan you have. Is it a small, 6" fan or, is it a "Fanstatik" fan with the full size, 14" fan? In either case, pull the screen down by undoing all the screws and figure out what's the cause of your problem. Maybe the screen has a warp to it in the "UP" direction. If so, warp it in the opposite direction. If the fan appears it's maybe not on the motor shaft far enough, then that may be harder to remedy.
Most of those units are encased in a plastic structure so, you won't be able to "tweak" the structure frame up a tad to create additional clearance between the fan and screen. But, I think you'' be able to come up with something create that needed tiny bit of extra clearance. Good luck.
2004 ITASCA HORIZON 36GD, 2011 GMC Sierra 1500 4x4 Toad '08 GL 1800 Gold Wing
Retired-29.5 yrs, SDFD, Ham - KI6OND
Me, Karla and the Sophie character, (mini Schnauzer)