iPhone 6 shows "not certified cable" and isn't charging
I am currently repairing a phone which I though had a lightning connector damage, as it showed "this cable or accessory is not certified and may not work reliably with this iphone" with all chargers and cables (i tried 3 different cables which work perfectly with other iphones). I tried plugging in another battery as the original one was completely empty, I can boot the phone but it still brings up this message everytime I connect the charger. I replaced the lightning flex as well but it still shows the same error message. Already tried cleaning the port but still nothing.
I think I've tried everything but I can't get the phone to charge.
Does someone have an idea?
Is this a good question?