How does the flow in your tank look?
What about everything else in your tank?
Age of tank?
Parameters and what you are using to test them?
Where did you get the coral from?
Both look like they are melting. Without more info from you, I would guess that the light is inadequate, likely not enough water movement either. You should share some info for us to help, something is wrong with the tank to have killed these 2 almost unkillable corals in just 5 days.