Accessing Microsoft Entra application proxy hosted API from Excel Add-in

Question

Hi, We have an excel add-in developed using javascript based on office.js library, it contains taskpanes, ribbon buttons/actions, custom function using shared runtime. Now we want to access one of our API secured using Microsoft Entra application proxy, but I am not able to find any sample code for it. When I try to call API operation using fetch, it gives CORS error in preflight and 404 error in network tab. I tried to resolve this CORS error by all methods defined on https://learn.microsoft.com/en-us/entra/identity/app-proxy/application-proxy-understand-cors-issues, but still error is there. It will be very helpful if a simple easy to use sample is provided for this scenario.