XMLHttpRequest cannot load (CROS)

Problem with Http.get
Trying to access rest api but stuck on testing
i can run the tutorial of http demo 10 minutes
but when i tried to consume my api the browser is giving me error regarding CROS

XMLHttpRequest cannot load "https://api.---------my url " Origin http://localhost:8100 is not allowed by Access-Control-Allow-Origin
tried to run on simulator android and ios but still getting white blank page.
Any suggestion