Fanta chicken

Hello all

I made this tonight and it was amazing it said on the recipe to leave for 20 mins but I left it more like 50 I was wandering how you make the sauce thicker mine was still so thin? Should I simmer for longer?

How high did you have the heat?

When I make diet coke chicken I have the heat up very high and after about 20/30 mins it goes all lovely and thick and sticky.