Sorry for the delayed reply. I assume you have already tried a different SIM apart from you original one and found the results the same - if not, then please try doing so and observe as SIM cards do fail a may give the SIM error you are receiving. Otherwise, if the result is the same with all SIM cards, then you may either have a bad or dirty SIM slot. You can try and clean in by dipping your SIM card and insert and remove it several times in the slot and let it to dry for 30min to an hour. The tab must be off during the suggested cleaning attempts to avoid shorting. Unfortunately, a bad SIM slot would mean that you will have to take it for service as it may range from a bent SIM pin to a burnt SIM IC. Let us know if you have any other needed assistance on this.