Question about Sony SAL-14TC, 1.4x telephoto lens

Yes, I bought the product, but unfortunately there is no function with the SONY SAL70400G2 lens. Maybe you have to adjust something on the Alpha99 camera?

With teleconverters, the lens plays a role. (Telephoto) lenses with an aperture of 2.8 to max. 4 should be used, then it works. With a lens of 100 or less, a teleconverter would not be needed. The 70-200mm 2.8 is very often used in this respect.