Hello and thank you for your question, I look forward to assisting you today. Are you see the error 01 message?
Okay, try this. Power the camera down and remove the lens. With the lens off, power on press the shutter button as though you were taking a picture. Power down then reattach the lens but do not lock it in place and take another picture. Power down then lock the lens then power back up and try shooting normally.
Did you clean the contacts on both the lens and camera body using alcohol?
Let me add some additional instructions to the lens reset I first sent. With the lens removed, take two photos then power the camera off. Turn the auto focus off on the lens and reattach it to the camera again without locking it in place and take one photo then check to see if the error is still visible. Turn the camera off and lock the lens in place and turn the auto focus back on and try taking another photo.