Hello Everyone

I got a problem

I have an GM 16-35 F2.8, the lens can't read the aperture, when it's connected to the camera(A7rii), my other lenses works fine. i do not know anything else besides that.

Has anyone else experienced something like that?, how much would it approximately cost to repair the lens? 

Regards Malthe
have a nice day, I hope you can help me