add details to aud mismatch message

backend/app/rest/api/rest_private.go

@@ -62,7 +62,7 @@ func (s *private) createCommentCtrl(w http.ResponseWriter, r *http.Request) {
 	user := rest.MustGetUserInfo(r)
 	if user.ID != "admin" && user.SiteID != comment.Locator.SiteID {
 		rest.SendErrorJSON(w, r, http.StatusForbidden,
-			errors.New("site mismatch, not allowed to post to "+comment.Locator.SiteID), "invalid site",
+			fmt.Errorf("site mismatch, %q not allowed to post to %s", user.SiteID, comment.Locator.SiteID), "invalid site",
 			rest.ErrCommentValidation)
 		return
 	}