R.NET 1.5.5 is obsolete; please use the latest NuGet package 1.5.16 which is likely to have resolved your issue, and if not you will very likely get more information as to the error, which will help other users to give you useful advice.
I regret there are two parallel nuget packages sources for R.NET, a likely source of confusion, but this is outside of my control.
I regret there are two parallel nuget packages sources for R.NET, a likely source of confusion, but this is outside of my control.