I feel like I cant breed any new dragons.

Is anyone else struggling to breed new dragons? Ive been playing this game on and off for over 10 years. Level 98, 168 dragons (no multiples) and Ive been playing again for the past few weeks and literally cant breed a dragon I dont already have. Ive looked at the wiki and used the breeding calculator but I keep getting dragons I already have. What am I doing wrong???