GoLang Ajax Gorilla sessions not saving

I am using GoLang as the back end for my web app. All is working well until I try and preserve the user login using the combination of Ajax/Gorilla Sessions and a browser.

When using a rest client the session is storing as expected, but when performing the same action in browser I first got a CORS error but after fixing that by using "github.com/rs/cors" the issue now is the session is not being preserved

Any help would be appreciated

var store = sessions.NewCookieStore([]byte("something-very-secret"))
func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("/set", SetCookie)
    mux.HandleFunc("/get", ViewCookie)
    handler := cors.Default().Handler(mux)
    log.Fatal(http.ListenAndServe(":8081", handler))
}

func SetCookie(w http.ResponseWriter, r *http.Request) {
    session, _ := store.Get(r, "kanban")
    session.Values["username"] = "edred"
    session.Save(r, w)
    fmt.Fprintln(w, "cookie saved")
}

func ViewCookie(w http.ResponseWriter, r *http.Request) {
    session, _ := store.Get(r, "kanban")
    fmt.Fprintln(w, session.Values["username"])
}