Welcome to the Candy Crush Saga Community
Do you have a question or need help with your game? Ask the Community.
What kind of mobile do you have? I suggest you try all of the following, it should fix most problems.
Restarting the device
Updating the version of Candy Crush Saga
Ensuring that you have enough memory space on your phone.
As a last resort (if you levels are synced on Facebook only) uninstall and re-install the game.
Let me know how you get on