iphone 6s says connect to itunes
my IPhone suddenly went black and wouldn't turn on i held power and home button for 50 secs and it eventually came on now it says to plug into itunes which i have done so and it has done nothing
iPhone 6s
You have to restore the phone. That's what the message means. Put the phone into recovery mode and restore.
If you can't update or restore your iPhone, iPad, or iPod touch - Apple Support