I've had this happen a few times. Assuming your gas is on at the tank, check to make sure your automatic shut-off switch has not been accidentally turned off. Mine is located on the kick board below the lav sink cabinet, which makes it vulnerable. Next, check that there is not a bubble of air in the lines that will prevent the fridge from kicking over to gas. You can do this by lighting a burner on the gas range. If it does not light immediately, an air bubble may be the issue. Once the burner catches, you may be able to light the fridge, although it may still take a few tries. Good luck.