The local computer IP address is not accessible from any application running on same computer.
If you have published the SignalR on IIS, then using the IP address you mentioned, it is possible to access the server in LAN.
If you want to access "localhost" on same computer, then simply replace "localhost" with ip address "127.0.0.1". This ip address is reserved for localhost and to be used only by local applications to access server.
For more information on "localhost" go through article;
localhost - Wikipedia, the free encyclopedia[
^]