ASP.NET Core 6 - How to correctly set up CORS for a Blazor WebAssembly app hosted with ASP.NET Core?
I'm currently working on a Blazor WebAssembly application hosted within an ASP.NET Core 6 backend and I'm experiencing CORS issues when trying to make API calls from the Blazor front end to the ASP.NET Core API. I have enabled CORS in my `Startup.cs` file, but I keep getting a `CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource` behavior in the browser console. Here's what I have in my `ConfigureServices` method: ```csharp public void ConfigureServices(IServiceCollection services) { services.AddCors(options => { options.AddPolicy("AllowAll", builder => { builder.AllowAnyOrigin() .AllowAnyMethod() .AllowAnyHeader(); }); }); services.AddControllers(); // Other service configurations } ``` And in my `Configure` method: ```csharp public void Configure(IApplicationBuilder app, IWebHostEnvironment env) { if (env.IsDevelopment()) { app.UseDeveloperExceptionPage(); } else { app.UseExceptionHandler("/Home/behavior"); } app.UseHttpsRedirection(); app.UseRouting(); app.UseCors("AllowAll"); // CORS middleware is placed here app.UseAuthorization(); app.UseEndpoints(endpoints => { endpoints.MapControllers(); }); } ``` The Blazor app makes a call to fetch data from my API like this: ```csharp var response = await Http.GetAsync("https://localhost:5001/api/data"); if (response.IsSuccessStatusCode) { // process response } else { // handle behavior } ``` I have also tried different approaches such as allowing specific origins and adding headers individually, but the question continues. I've verified that the API is running on `https://localhost:5001` and the Blazor app is served from `https://localhost:5000`. I have confirmed that the API endpoints are reachable by making requests directly through Postman. What am I missing here that could be causing the CORS behavior, and how do I ensure that CORS is properly configured for my Blazor WebAssembly app?