Such issues comes mainly when you update or upgrade your system OS to latest version. To fix this problem follow the steps given below:
Step1: On your Mac, select from the Finder Menu Go -> Go To Folder… and type
“/Library/Preferences/SystemConfiguration” in the following path and press enter...
Visit this Apple official link https://support.apple.com/en-us/HT204990 for install Boot Camp for windows 10. If you are not able to installed Boot Camp through this link then call Apple support official Number (USA Toll-free) and find instant support by apple technicians.