Here are the steps to help track down the problem:
1. Deactivate all of your plugins
2. Activate a default theme like TwentySeventeen
3. Activate W3 Total Cache
4. If you don’t get the error, activate each of your other plugins one by one until you see that same error. Then you’ll know there is a conflict between that plugin and W3 Total Cache.
5. If you’re able to reactivate all plugins along with W3 Total Cache on a default theme, then reactivate your theme. If the fatal error comes back when you activate your theme, that’s where the issue probably lies. So you’ll probably need to post in that theme’s support forums on www.ads-software.com.

Hope that helps and let me know if you have any questions.