Web services not showing results.... cors error occur

Dear All,
I want to use a web api in ionic . but result cannot be shown…
when i use a different api i.e (swapi.co/api/films/) its show a result… but my api cannot show the results. it will generate a error i.e
"
Failed to load strong texthttp://online.efuinsurance.com:9003/Web_Master_App/eMisc/country: No ‘Access-Control-Allow-Origin’ header is present on the requested resource. Origin ‘http://localhost:8100’ is therefore not allowed access.

Add the missing header to the response of your API as it says in the error message.

how can i add header?
@Sujan12

I can not tell you that, as it is part of the API you are using at http://online.efuinsurance.com:9003/Web_Master_App/eMisc/country. This URL has to return the hedaer.

yes. i can use this API to call data but CORS error generate… How to add header kindly guide me
@Sujan12

See my previous answer. I can not tell you more than that: The API has to return that header in its response.