I have had my Note 8 about a year now and the past week I have been randomly getting a Sim Card Error. It doesn't matter the time of day, I can wake up in the morning and this error is on my phone. I have done the update profile and prl to see if that helps, then I restart my phone and of course it goes away but then it happens again later that day or the next day.
Sorry to hear you are having issues with your Note 8 Sim card. Can you please tell me the specific error you are getting?