Default How come my I9300 will not detect certain sim cards?

Hello guys, I have the international GS3 i9300 model and for some reason when I tried to put in an LTE sim card from fido it didn't detect it. All it shows me is that there is no sim inserted. It does however detect sim cards from Rogers and Koodo because I have used it on those carriers before. Any clue as to why it won't even detect it?