Hi guys,

Full disclosure: I am a linux guy and am entirely out of my depth here.

The setup: I have [perhaps mistakenly] offered to host an old C# dotnet web app for a mate, on Linux. I have installed Visual Studio Code, dotnet core sdk (2.1.503) and SQL server on my machine (as a docker instance). So far, fairly smooth sailing.

The problem: When I cd to the project directory and type 'dotnet run' I get the following error message, and I do not know what I don't know to resolve it:

$ dotnet run /usr/share/dotnet/sdk/2.1.503/Microsoft.Common.CurrentVersion.targets(1179,5): error MSB3644: The reference assemblies for framework ".NETFramework,Version=v4.0" were not found. To resolve this, install the SDK or Targeting Pack for this framework version or retarget your application to a version of the framework for which you have the SDK or Targeting Pack installed. Note that assemblies will be resolved from the Global Assembly Cache (GAC) and will be used in place of reference assemblies. Therefore your assembly may not be correctly targeted for the framework you intend. [/home/projects/some_shitty_project/project.csproj] 

In noob terms, what does this mean and how should I fix it?

FWIW i think the relevant lines in the .csproj file is:

 <TargetFrameworkVersion>v4.0</TargetFrameworkVersion> 

Any tips or advice on how to proceed would be greatly appreciated.

Cheers.