Accessing endpoints published to Entra Application Proxy from SPFx

We have an on-premises web service (hosted in IIS) published through Entra Application Proxy.

When attempting to access the published endpoints from a SharePoint (SPFx) web part, we encounter CORS errors (302 Found). Accessing these endpoints directly from a browser address bar works as expected.

In IIS, the Access-Control-Allow-Origin response header is set to * (wildcard). We have also tried specifying a particular domain, but that did not resolve the issue.

Pre-authentication is enabled in Entra Application Proxy.

Has anyone successfully connected to endpoints behind Entra Application Proxy from an SPFx web part? Any insights or solutions would be greatly appreciated.