Welcome to the Candy Crush Saga Community
Do you have a question or need help with your game? Ask the Community.
If that's the case the only thing to do is take a screenshot of the end game message and post it here so it can be looked at. Without the screenshot, there's no way to tell. Seeing as level 266 has candy bombs in it, my guess is that a candy bomb was about to explode which is why it was considered failed.