a problem while updating new ios 10

dear ,

i have downloaded the new update direct on my Iphone 6 s plus , BUT MAY BE There WAS disconnecting during downloading , now when i press install the software , the message comes to me after verifying :

IOS 10 failed verification because you are no longer connected to the internet >>>???

so what to do ?? , also i tried to update using itunes also a message comes to me "there was a problem downloading the software for the iphone "iphone name" An Unknown error occured (-39)