Negotiate defaults returns 401 on IIS-hosted MVC page, but works when accessed directly

I’m hosting a C# MVC application on IIS. When I navigate to one of the pages, there’s a component on that page that attempts to call an endpoint which uses Negotiate authentication defaults. However, it returns a 401 Unauthorized error.

Strangely, if I access that specific endpoint directly in the browser, it successfully performs Negotiate authentication and returns the expected result.

Why does it return 401 when called from the page/component, but work fine when accessed directly? How can I fix this?

Any help would be appreciated!

Note: I already enabled windows auth in iis

Note: I already enabled windows auth in iisIt worked on local but not on the server