Sims 4 ERROR CE-34878-0?

The error is a PS4 error to say that the software crashed.

Below are some ideas on how to fix the problem

Restart your console:

• Turn off your console and then turn it back on.

Make sure your game software is up to date:

• Go to the PlayStation home screen. 
• Highlight the game you're playing and press the Options button on your controller.
• Select "Check For Update" and install any updates that are available.

Make sure your PS4's system software has the most recent update:

• Select Settings at the top of the PlayStation home screen.
• Choose "System Software Update" and allow any system updates to install.
• Reboot your PlayStation 4.

Clear your PS4's cache:

• 
  

  The PlayStation 4 doesn't actually have a cache to clear. That said: It never hurts to power down/power up your console if you're encountering performance issues in the console. 

  1. Press and hold the PlayStation button on your controller. 
  2. Select "Turn Off PS4". 
  3. Let the PlayStation 4 to fully power down and wait for 10 to 20 seconds.
  4. Restart the PlayStation 4.

 Uninstall/reinstall your game: 

• So you're still having problems? OK, you may want to think about uninstalling/reinstalling the game experiencing the error. 
• Before you do this, upload your save game to the cloud (or to a USB storage device). That way you won't lose your progress and have to start over once you've reinstalled.
• OK, once you're ready to uninstall your game data from the console, follow this guide SCEA put together over at their official site.

Reinstall the original hard drive:

• This is only if you have upgraded your PS4's hard drive (read: replaced it with a larger one). Sony suggests re-installing the original hard drive that came with the console. 

If none of these steps have helped, you should reach out to PlayStation Support.