diff --git a/racketmq/hub/remote-topic.rkt b/racketmq/hub/remote-topic.rkt
index e3b4e81..fbf8c33 100644
--- a/racketmq/hub/remote-topic.rkt
+++ b/racketmq/hub/remote-topic.rkt
@@ -77,7 +77,8 @@
 
     (define/query-config max-upstream-redirects 5)
 
-    (on (asserted (later-than (+ (last-upstream-check) (* 1000 (or (poll-interval-seconds) 0)))))
+    (on #:when (poll-interval-seconds) (asserted (later-than (+ (last-upstream-check)
+                                                                (* 1000 (or (poll-interval-seconds) 0)))))
         (log-info "Checking upstream ~a" full-topic)
         (define-values (resp response-body)
           (web-request! 'get full-topic #:redirect-budget (max-upstream-redirects)))