I recently replaced a lost key and FOB for my 2011 Hyundai Elantra. The key will make the engine turn over but it won't start. The old key works fine.
Hyundai's outside of the US are equipped with immobilizer systems and new keys need to be programmed to the car. Since the immobilizer system is not accepting the code from the unrecognized key it is telling the engine controls to shut down the spark and fuel. To have the key matched you can call a local locksmith or take it to the dealer.