Once in a while, we remove our SIM cards so we can change service providers or for whatever reason then return them in our iPhones. unfortunately, once this happens, iMessage and FaceTime also stop working and you will need to activate it once more so you can continue using it as you normally do. This method also applies when activating iMessage and FaceTime for the first time, not necessarily after removing your SIM card. Note that this method works for iPhones, iPad, and all other iOS devices. iMessage and FaceTime Activation Notice Your iPhone will show this message once you reinsert your SIM Card prompting you to activate iMessage and FaceTime: FaceTime and iMessage Your network provider may charge for SMS messages used to activate FaceTime and iMessage. Click okay then proceed with the steps below: Once you are done with the steps above, your iMessage and FaceTime will be activated in a few minutes. Wait for it it happen as it is not instantaneous.