Blazor Request blocked by CORS policy

Question

I am trying to send a request from a Blazor(client-side) client to a server and i keep getting this error:

Access to fetch at '[route]' (redirected from '[other route]') from origin '[origin route]' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

On the server i have already added the CORS extension in the pipeline to no avail:

Server Startup

public void ConfigureServices(IServiceCollection services) {
            services.AddCors();
            services.AddResponseCompression(options => {
                options.MimeTypes = ResponseCompressionDefaults.MimeTypes.Concat(new[]
                {
                    MediaTypeNames.Application.Octet,
                    WasmMediaTypeNames.Application.Wasm,
                });
            });
}
 public void Configure(IApplicationBuilder app, IHostingEnvironment env) {

            app.UseCors(x => x.AllowAnyHeader().AllowAnyMethod().AllowAnyOrigin().AllowCredentials());

            app.UseResponseCompression();

            app.UseMvc();

            app.UseBlazor<Client.Startup>();

        }

Blazor Client request

public async Task<Catalog> GetCatalogAsync() {
            try {
                HttpRequestMessage message = new HttpRequestMessage {
                    RequestUri = new Uri(BASE_PATH + Routes.GET_CATALOG), //BASE_PATH= 172.XX.XX.XX:8600
                    Method = HttpMethod.Get
                };
                var resp = await this.client.SendAsync(message); // client is HttpClient
                var resultString = await resp.Content.ReadAsStringAsync();
                var result = JsonConvert.DeserializeObject<Catalog>(resultString);
                return data;

            } catch (Exception ex) {

                throw;
            }

        }

Controller

[HttpGet]
[Route(Routes.GET_CATALOG)]
public async Task<Catalog> GetCatalogAsync() {
    try {
        var registry = await this.adminService.GetCatalogAsync();
        return registry;
    } catch (Exception ex) {

        throw;
    }
}

POCO

[Serializeable]
public struct Catalog{
}

What else can i do to be able to reach my server? Is it due to Blazor ? As you can see i have already added the UseCors(...).

P.S
I have published my Blazor Server project together with the Client.They are in the same directory.This folder i placed it on a computer,and i am trying from my computer to open blazor : 172.168.18.22:8600/

Update
I have also tried adding headers to my HttpRequestMessage to no avail:

HttpRequestMessage message = new HttpRequestMessage {
                    RequestUri = new Uri(BASE_PATH + Routes.GET_CATALOG),
                    Method = HttpMethod.Get,

                };
message.Headers.Add("Access-Control-Allow-Origin","*");
message.Headers.Add("Access-Control-Allow-Credentials", "true");
message.Headers.Add("Access-Control-Allow-Headers", "Access-Control-Allow-Origin,Content-Type");

Answer 1

Somehow the problem was due to a very old client version that was cached on the browser.Never again will i forget to clear the browser cache after this problem. Thank you all for your help and support !