Unable to activate

Hi, I recently repaired my iphone (changed lcd, back cover and sim ic) as it was fallen down and damaged. After repairing it, i tried to restore back up from my itunes it was not happening, so I thought i do reset and then backup from itunes. but after reseting the phone is not activating. it is showing the following message. "Your iphone could not be activated because the activation server cannot be reached. Try connecting your iphone to itunes to activate it, or try again in a couple of minutes. if this problem persists, contact apple support at apple.com/support" I did try again but still same. Could anyone please help me in this. This phone is really important to me.