Malfunction

Hello, I was on the phone with bf yesterday and my phone hung up and said “no sim” and where my bars were at there were three dots. I tried turning it on and off multiple times as well as toggling airplane mode too. I tried turning it on and off again and finally after two hours it started working again. I googled this and it mentioned updating the phone. I havnt updated my phone yet so im hoping it is because of that. So i guess my question is, have you heard of that happening before? Do you think it’s because i havnt updated?

Im only asking because im hoping there isnt a bug and i dont have to take my phone in