cannot activate my ipad after upgrade ios 8.4.1

I can not activate my ipad after i upgrade ios 8.4.1.My ipad is 3rdgeneration wi+cellular A1430 model 64G.
I used wifi.I notice when i pull out sim card from my ipad I can use my ipad normally .When I insert sim card
Activation Required message appear then I activate it but Activation fail message appear.I cannot use any apps
even i cannot use setting application.Now I download ios 8.4.1 firmware to reset my ipad.Is it right? :)