Are you trying to summon it with Cyber Style? Because in that case, you can't. Cyber Style can only be used for Fusion summoning.
*Make sure that all requirements were met!
Cyber Laser Dragon can only be special summoned by Photon Generator Unit, on which the card text says
"Tribute 2 Cyber Dragons. Special Summon 1 Cyber Laser Dragon from your hand, Deck, or Graveyard".
Make sure that you all requirements were met!