I brought an iPhone 6 recently, it charges just fine with the charger supplied, but the other day I brought 2 new cables one cheapy from KMart the other a good certified brand from Dick Smiths Electronics, both of them come up with the this accessory may not be supported message and do not appear to charge the phone...the genuine cable still works just fine!
This is a big issue for me, if Apple have done this deliberately so that I have to buy their branded cables only and cannot use any other...it is likely I will never buy Apple again, every thing I have read so far people seem to think it is only happening with cheap or damaged cables, but it seems deliberate to me - I can plug my expensive OEM apparently certified cable in and not be supported and not have it work and then plug the apple cable into the same outlet (same apple charger unit) and have it work just fine...