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

Hi everyone! I'm a beginner in C# and encountered a problem when debugging in Visual Studio Express. I have a simple console application, but when I set a breakpoint on some line of code, for example, on `Console.WriteLine("Hello");`, Visual Studio shows a warning: "The breakpoint will not currently be hit. No symbols have been loaded for this document." The breakpoint becomes transparent with a white circle and an exclamation mark. I tried rebuilding the project (Build -> Rebuild Solution), cleaning the solution and rebuilding, but it doesn't help. Sometimes breakpoints work, and sometimes they don't. I noticed that this happens when I change the code and start debugging without a full rebuild.