Error Implementing Authentication in Xamarin

I am following along the tutorial on how to add Okta authentication to Xamarin apps ( ). I am getting an error trying to install a nuget package that the tutorial requires. The package is called System.IdentityModel.Tokens.Jwt and I am getting the following error: Could not install package ‘System.IdentityModel.Tokens.Jwt 5.3.0’. You are trying to install this package into a project that targets ‘.NETPortable,Version=v4.5,Profile=Profile111’, but the package does not contain any assembly references or content files that are compatible with that framework. For more information, contact the package author.

I am hoping that there is another package that I can use or maybe some way that I can modify the code form the tutorial so that it will still work