✅ ASP.NET Core Environment Variables: missing Parameter "clientSecret" for EntraId

builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
                .AddMicrosoftIdentityWebApi(azureAdConfig)
                .EnableTokenAcquisitionToCallDownstreamApi()
                .AddInMemoryTokenCaches();

string instance = Environment.GetEnvironmentVariable("ENTRA_INSTANCE") ?? throw new Exception("Missing Environment Variable ENTRA_INSTANCE");
string clientId = Environment.GetEnvironmentVariable("ENTRA_CLIENT_ID") ?? throw new Exception("Missing Environment Variable ENTRA_CLIENT_ID");
string tenantId = Environment.GetEnvironmentVariable("ENTRA_TENANT_ID") ?? throw new Exception("Missing Environment Variable ENTRA_TENANT_ID");
string entraScope = Environment.GetEnvironmentVariable("ENTRA_SCOPES") ?? throw new Exception("Missing Environment Variable ENTRA_SCOPES");

builder.Configuration.AddKeyPerFile(directoryPath: "/run/secrets", optional: false);

var azureAdConfig = new ConfigurationBuilder()
    .AddInMemoryCollection(new Dictionary<string, string>
    {
        {"AzureAd:Instance", instance},
        {"AzureAd:TenantId", tenantId},
        {"AzureAd:ClientId", clientId},
        {"AzureAd:Scopes", entraScope}  
    })
    .Build();
...
.AddMicrosoftIdentityWebApi(azureAdConfig)

System.ArgumentNullException: Value cannot be null. (Parameter 'clientSecret')