Have you ever been casually browsing Instagram (or any other app) when suddenly your phone pulls a fast one on you with that “No SIM” notification? That can be pretty inconvenient. But imagine this happens when you need to make a call, especially in an emergency situation. What does this mean? And, more importantly, what can you do about it? Why is my phone saying no SIM?This unsettling alert often means your phone can’t detect the SIM card that’s supposed to link you to the outside world. Here are some of the usual culprits: Faulty installation: The SIM card might not be sitting snugly in its…