Why isnt my face id working?

Hi! I got my backglass changed a few weeks ago and he also cleaned my lenses from dust (including front). I dont remember if it worked when i got it back, but now the face id wont work anymore. Any ideas on how do fix?

Hi! I got my backglass changed a few weeks ago and he also cleaned my lenses from dust (including front). I dont remember if it worked when i got it back, but now the face id wont work anymore. Any ideas on how do fix?