I tried to compile my new application in MonoDevelop and I got this error:
/usr/share/dotnet/sdk/2.2.203/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.
I had this error happen and the slove for me was correcting the Package version number in .csproj file .
2.0.7. 2.0.7
Removing the trailing '.' fixed this for me.