Nyakoi moje li da mi obyasni kak da resha tozi probelm i kakvo oznahava:

Compiled file is missing. Compiler output: Microsoft (R) Build Engine version 16.3.0+0f4c62fea for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

C:\Program Files\dotnet\sdk\3.0.100\NuGet.targets(123,5): error : Unable to load the service index for source https://api.nuget.org/v3/index.json. [...\NUnitLiteConsoleApp.csproj]
C:\Program Files\dotnet\sdk\3.0.100\NuGet.targets(123,5): error :   An attempt was made to access a socket in a way forbidden by its access permissions. [...\NUnitLiteConsoleApp.csproj]

Build FAILED.

C:\Program Files\dotnet\sdk\3.0.100\NuGet.targets(123,5): error : Unable to load the service index for source https://api.nuget.org/v3/index.json. [...\NUnitLiteConsoleApp.csproj]
C:\Program Files\dotnet\sdk\3.0.100\NuGet.targets(123,5): error :   An attempt was made to access a socket in a way forbidden by its access permissions. [...\NUnitLiteConsoleApp.csproj]
    0 Warning(s)
    1 Error(s)