Q: Trying to activate my FaceTime in settings keep saying unsuccessful what should I do

FaceTime and FaceTime audio calling might not be available for all countries, regions, or carriers.

Get help if you can't make or receive FaceTime calls - Apple Support

I was curious as to why Curacao (from your UserName) might not be on the list of countries - a "constituent country" of the Kingdom of the Netherlands - my conclusion is "too small to list"

USING FaceTime only requires an adequate connection - High Speed

In poking around in Carol's 2nd link, I found this where your reported error is listed

If you get an error when trying to activate iMessage or FaceTime - Apple Support