I requested a new password during the iWatch pairing but the phone screen went black, why?

I am attempting to pair my I watch with my iPhone, however, I forgot the password. When I press "forgot password" the I phone blacks out and stays black; so I can't continue the pairing.

Make a Genius Bar appointment with the nearest Apple Store to have the problem with your Apple Watch. Be prepared to prove your identity and that the watch and associated account is indeed yours.