Facetime And Imessage activation fail on IOS 6.1

on my iphone 4
When i was on 5.1.1 my imessage and facetime was working perfectly fine since i have updated to ios 6.1 imessage and facetime wont activate saying that the id and password is incorrect wheresas with the same id and password im downloading apps..
the network and Wifi are same..
HELPPPPP!!!!! please