Update 2

Homework/Program.cs

@@ -30,7 +30,14 @@ builder.Services.AddCors(options =>
 // ======================
 var jwtSettings = builder.Configuration.GetSection("JwtSettings");
 
-var key = Encoding.UTF8.GetBytes(jwtSettings["Key"]);
+string? secretKey = jwtSettings["Key"];
+
+if(string.IsNullOrEmpty(secretKey))
+{
+    return;
+}
+
+var key = Encoding.UTF8.GetBytes(secretKey);
 
 // ======================
 // Lägg till JWT Authentication
@@ -84,4 +91,4 @@ app.UseAuthorization();
 
 app.MapControllers();
 
-app.Run();
+await app.RunAsync();