I am a returning player to dragon city.Used to play back in 2014.There was no Heroic dragon at that time and a lot of things have changed. I got the cool fire dragon by breeding ice and flame dragon at that time but now, it does not let me do that and I need that type of dragon for the frozen wind cup. How can I get the dragon by breeding?

Are you positive you did not use a hybrid as far as I know it has never been possible to use ice and fire to breed together. But see here as this has been recently posted and is being discussed for this very issue. Closing this as a duplicate.