Hace un año no juegaba en mi dragonario tenia mis legendarios y algunos mas actualmente no me sale los dragones y cuando intento abrir mas eslots me sale error y se reinicia el juego o carga

You did not state what device you are playing on. If on mobile, I would suggest deleting the game and doing a fresh install from your App Store. As long as your game is associated to Facebook, you won't lose your progress.

If playing on Facebook, clear your cache files and make sure that your browser and flash player are both up to date.

If that does not help, submit a detailed bug report. The instructions are in my signature line.