The error code CE-34878-0 is often connected with file corruption issues on your PlayStation 4 - it may indicate a damaged PlayStation operating system or game install. Commonly suggested fixes include:
- Restarting the PS4 console
- Make sure your PS4 system software is fully up to date
- Try reinstalling the game if you're experiencing this error only in one particular game
You may also wish to try re-initializing your PS4 operating system. You can do this by going to Settings -> Initialization, however, I wouldn't suggest doing this unless the other suggestions don't help.