Watch Only bitcoin address

Hello !

when i open my blockchain account i not found my old address it was deleted and make import for it and appear watch only, so How i make activate for my Watch Only bitcoin address, and how i have private key scean QR code not work ?! 

this message appear : You may add a Watch Only bitcoin address to your wallet. You will not be able to send bitcoins from this address without later providing the private key .

Thanks, Aiman Magdi