Failed to load index.html try again later issue in ionic 4

I have strange issue.
I have globally installed ionic 4 latest version.

When I create ionic 4 project and run in browser using ionic serve it works fine, everything is fine.

When i try to create ionic 3 project using this below command:
ionic start myApp blank --type=ionic-angular
It successfully creates app but when I run it using ionic serve then browser shows try again later.
CLI shows Failed to load index.html
I see no index.html file is generated in www folder but it is available in src folder.

I tried all things like npm update, npm install, delete node_modules folder. Nothing helps. Always shows error. Screenshots attached.