unable to install whatsapp in iphone 4s

[iMore Question]

i downloaded whatsapp from itunes store and while trying to load in my iphone 4s it is not installing. i tried to drag it on to iphone but it is showing will install

 

[phreddyl]

Does it show installing on your phone? If so I would delete it and try to install again. Do you have a good signal?

 

[Chitipotu Mani Deepti]

Forgot my Apple ID and password