How to fix the error "The breakpoint will not currently be hit. No symbols have been loaded for this document" in C#?

Hi everyone! I'm a beginner in C# and Visual Studio, and I'm having a problem with debugging. I'm writing a simple console application on .NET Framework 4.7.2. I have two projects in one solution: the main project (MyApp) and a class library (MyLibrary) that I reference. Here's an example code in my library: ```csharp namespace MyLibrary { public class Calculator { public int Add(int a, int b) { int result = a + b; // Breakpoint here return result; } } } ``` In the main project I call this method: ```csharp using MyLibrary; using System; namespace MyApp { class Program { static void Main(string[] args) { var calc = new Calculator(); int sum = calc.