How to resolve CORS issue for calling non-sap API on-premise?

Hi All,

I am trying to call a non-sap api using ajax which works fine from Cloud(setting a destination on SCC/BTP) but not when its deployed to on-premise FLP.

We added 'Access-Control-Allow-Origin' header response parameter in service API but still no luck.

Is there any issue in UI5 that it requests a preflight call internally?

Let me know if anyone had similar issue.

Thanks in advance!

Regards

Kriti