Works on mobile app but when used on Win Forms throws html error

[DwainSnickles]

I am getting an html error when trying to use on windows forms the error is
What I found was an inner exception could not load System.Encoding.Codepages version = 6.0 does any one know how I get around the the version 6 issue when using framework 4.72 .net framework the other program uses .net core 5.0

[DwainSnickles]

Argh just had to install the nuget package sorry still a rookie.