Build Errors says that debug target is missing even when building the solution & projects

Hello, New to .NET here. When I try to run my code i get these errors as shown in the image (my code: https://github.com/zheliya/Part18BetterGuestBook) and even when I click on ok to run the project I get these two errors in the image I have checked both the OutputPath and AssemblyName for ConsoleUI, and I also double checked if the the other project reference is added to the ConsoleUI, and it's also set as the startup project too. so i don't understand why it's not working. i also tried rebuilding the solution and each of the projects too, i also uninstalled any antivirus application that i had previously.