Many users assume their 16 digit code is their password forever. It is not. After the first activation, Sygic converts that code into a standard user account. If you get a new phone, do not re-enter the 16 digit code; select instead. The code is only for the initial conversion.
If you bought a boxed version of Sygic from a brick-and-mortar store, the code is printed on a scratch-off card. Look for a silver foil panel on the back of the booklet or inside the DVD case. Scratch gently to reveal the 16 digits. sygic 16 digit activation code