Client Program cannot call IdentityServer in the QuickStarts basic program - identityserver4

Question

I'm planning to use Identity Server 4 in our B2C Site, and started learning Identity Server. For the beginning, I down downloaded Sample QuickStarts source code from your github page.(https://github.com/IdentityServer/IdentityServer4/tree/main/samples/Quickstarts)
Problem occurred soon after I started debugging '1_ClientCredentials' program, which I can't come up with the solution.
The failure occurs in the Main method of the Program class of the "Client" project.
namespace Client
{
public class Program
{
private static async Task Main()
{
// discover endpoints from metadata
var client = new HttpClient();
var disco = await client.GetDiscoveryDocumentAsync("https://localhost:5001"); **//<=Here!!**
if (disco.IsError)
{
Console.WriteLine(disco.Error);
return;
}
････
The 'IsError' property of the return value of the method is always true, so the client program is not able to proceed from then on.
The url 'https://localhost:5001' is valid, as I confirmed the url'https://localhost:5001/.well-known/openid-configuration' shows the correct json output on the browser.
What I'd like to know is how to let the HttpClient instance receive resonse for the document request.
For your reference, I have put the program in question in my GitHub repository below.
https://github.com/TrailRunner-MF/Samples/tree/master/QS1_ClientCredentials
Solution name is slightly different from the original, but the action is completely the same, especially when it stops at the location I mentioned
The solution name is slightly different from the original, but program code is the same except 'IdentityServer' project output letter's on the browser.
I hope someone might download them, build them, start debugging by setting 'Client' project as a startup project, and confirm if the problem occurs or not.And show me the solution for this problem.
Thank you.

Answer 1

The problem was solved in a simple way.
I have to set the solution as 'Multi start up project'.
(I had thought IdentityServer and Api would be kicked automatically by dependancy relation between projects inside the solution. But it was wrong.)
The way it was done is as follows.
Select 'Property' in the context menu of the solution.
Choose 'Multi startup projects' in the Property Page Dialog.
Set the Action as 'start' for each projects.
After than, I can proceed the debugging by clicking 'Start Debugging' button as I show below.
Thank you.