Why Nikon d3500 with Longteng 18-270 lens front camera is useless?

Some Longteng lenses have compatibility problems with Nikon D6 cameras.

After installing the lens with the camera power off, autofocus will not work when the camera is turned on. After the camera starts from sleep mode, autofocus doesn't work. At present, Longteng is investigating the causes of compatibility problems and will announce solutions in the future.