diff --git a/lib/passport-cas.js b/lib/passport-cas.js
index 52f1c33..111718a 100644
--- a/lib/passport-cas.js
+++ b/lib/passport-cas.js
@@ -168,7 +168,7 @@ CasStrategy.prototype.authenticate = function(req, options) {
 
   if (!ticket) {
     // Redirect to CAS server for authentication
-    self.redirect(self.casBaseUrl + '/login?service=' + encodeURIComponent(service), 307);
+    self.redirect(`${self.casBaseUrl}/login?service=${encodeURIComponent(service)}/?_cas_retry=${Math.round(date.getTime() / 60000)}`, 307);
   }
   else {
     // User has returned from CAS site with a ticket