Error:iBall Andi 4L Pulse-8004884b updating whatsapp windows 8.1 phone

Sir,
I am facing problem with my iBall Andy 4L pulse windows phone. The phone can't update whatsapp and because of that I can't use whatsapp at all. When I open whats app, it gives error that whatsapp has expired and you update it. So when I click update, after some long wait it gives following error :


There has been problem completing your request . Try again later.

This error code may be helpful : 8004884b


I tried restarting my phone, also tried different internet connection (my home wifi instead of cellular data connection). My phone has around 500mb internal storage free and has a 8GB card in it. Please help how can I solve this problem ?

Have you changed anything in your microsoft account ? Change in password etc. ?
May be you should go to settings --> account and click to verify it, if any problem then MS will automatically ask to verify and will send you code on secondary mail or phone number. After that you should be good to go.