Azure authentication Audience validation failed

I’m afraid the issue comes from the auth configuration in startup. Pls allow me show my code snippet to explain it well.

In my opinion, you could use services.AddMicrosoftIdentityWebApiAuthentication(Configuration); instead. And you should exposed the api correctly.

The steps of exposing api, you can follow the documents. What I wanna repeat here is when you generate an access token, it should have the scope like api://clientid_of_the_app_exposed_api/tiny/User.Read which can match the configuration in appsettings.json

My react code, it is referred to this sample:

import { AuthenticatedTemplate, UnauthenticatedTemplate, useMsal } from "@azure/msal-react";  
const callApi = (accessToken) => {
            const headers = new Headers();
            const bearer = `Bearer ${accessToken}`;
    
            headers.append("Authorization", bearer);
    
            const options = {
                method: "GET",
                headers: headers
            };
    
            fetch("https://localhost:44341/api/home", options)
                .then(response => {
                    var a = response.json();
                    console.log(a);
                })
                .catch(error => console.log(error));
        };
    
        const ProfileContent = () => {
            const { instance , accounts} = useMsal();
            const [graphData, setGraphData] = useState(null);
            const loginRequest = {"scopes": ["api://clientid_of_the_app_exposed_api/tiny/User.Read"]};
        
            function RequestProfileData() {
                instance.acquireTokenSilent({
                    ...loginRequest,
                    account: accounts[0]
                }).then((response) => {
                    callApi(response.accessToken);
                });
            }
        

My ConfigureServices in startup file, these are referred to this document:

public void ConfigureServices(IServiceCollection services)
        {
            services.AddCors(o => o.AddPolicy("MyPolicy", builder =>
            {
                builder.AllowAnyOrigin()
                       .AllowAnyMethod()
                       .AllowAnyHeader();
            }));
            services.AddMicrosoftIdentityWebApiAuthentication(Configuration);
            services.AddControllers();
        }

My appsettings :

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*",
  "AzureAd": {
    "Instance": "https://login.microsoftonline.com/",
    "ClientId": "clientid_which_have_api_permission",
    "Domain": "tenantname.onmicrosoft.com",
    "TenantId": "common",
    "Audience": "clientid_of_the_app_exposed_api"
  }
}

My controller:

using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Identity.Web.Resource;
using System.Collections.Generic;

namespace WebApplication1.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    [Authorize]
    public class HomeController : ControllerBase
    {
        [HttpGet]
        [RequiredScope("User.Read")]
        public ActionResult<IEnumerable<string>> Get()
        {
            return new string[] { "value1", "value2" };
        }
    }
}