Angular 4: CORS Issue on Post using ionic 3 angular 4

I really appreciate the guidance I'm getting from the community. Hence, i would like to ask a question please do note that I have exhausted all my resources and Google to figure out a solution for the issue:

Front-End: Using ionic3 angular 4

Back-End: Using Laravel 5.4

What we have tried so far:

Front End:

• Installed cordova whitelist plugin

• Added Proxy Url in config.xml

Back End:

• Added whitelisting and header for Laravel

The Issue:

XMLHttpRequest cannot load

http://ift.tt/2gVTRGN. Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8100' is therefore not allowed access.

Any valuable input would be greatly appreciated. Thanks.

via Chebli Mohamed