You need to use a modified version of SignalR for this to work. The relevant change is here https://github.com/jkells/SignalR/commit/58e6b9a3c01349f09b7d5e198cd673684e64b3ae
A prebuild package with that change is in this MyGet feed version 2.2.1.1 https://www.myget.org/F/jkells-public/api/v3/index.json