error NU1100: Unable to resolve 'Microsoft.NETCore.App.Runtime.win-x64' for 'net5.0', 'Microsoft.WindowsDesktop.App.Runtime.win-x64' for 'net5.0', 'Microsoft.AspNetCore.App.Runtime.win-x64' for 'net5.0'.
Solution 1: this might be due to bad gitlab package connection, reset the nuget package can help.