High failure rate

I had been with the dongle with the exception of a crash at the first use no problems. The I tested Android apps worked without any complaints with the dongle in all used vehicles (BMW 1-series, Opel Zafira, Porsche Macan, Toyota IQ). Boats he does very quickly and is already recognized a few seconds after plugging the cell phone.
However, the failure rate seems to be very high. 3 of my work colleagues have also bought the unit in 2 of which the dongle was without function.