I don't remember but I think I did updated the OS and didn't check if the SIM was working or not.
Current OS: 7.10.8107.79
Here's a thing. I restored it back to an earlier backup and the SIM was working again. I then factory reset it and got the SIM error again.
Now I restored to the same backup and the SIM is no longer detected, I have no idea why.
Any help would be much appreciated.