After the Instant Breeding update was released, regular back-breeding using the 'Go to crossbreed' option was no longer available in the game. As such, back-breeding has proven to be a bit more complicated after this update. While this is being investigated by the team, we advise that players follow this workaround instead:

  1.  Figure out the dragons you would like to back-breed by going to Red's guide here: https://docs.google.com/spreadsheets/d/1MQ_zjstJJGdT-WALWb4vr-lUZRz-vo3xtLfK3IldaVg/htmlview?usp=sharing&sle=true
  2. Go to your Breeding Castle then manually set the parents(as per step 1)
  3. Use the Instant Breed option to get the research eggs you require.

We appreciate everyone's patience while this is being looked into by the team.