Cannot register RestSharp Dll in GAC

[Dumbu D]

Hi All,  I have downloaded restSharp from Nuget package manager and it works fine with my VS projects.

But I am trying to use the RestSharp in SSIS Package Script Task where I did try adding RestSharp via Nuget but seems like there is some issue with it.

when I look at the GAC manager I cant seem to register the dll there. It simply says failed to register.

Please help me on how to register RestSharp to GAC so hoping my Script task in SSIS wont break.