Causes of an interruption to your service range from a setting on your handset to a faulty SIM card. To fix this problem, try the tips listed below. For comprehensive steps on how to action each tip using an iPhone 12 or iPhone 12 pro handset, refer to the “Could Not Activate Cellular Data Network” on iPhone 12 or iPhone 12 pro section of this article. • Make sure you’re not in Airplane mode • Make sure your cellular data is switched on • Make sure you have the latest iOS version installed • Toggle your LTE data button off then on again • Check for a carrier settings update • Reset your network settings • Restart your Phone • Replace your SIM card. If none of the above work, contact your carrier provider to rule out any problems with your plan.