diff --git a/rmq/main.rkt b/rmq/main.rkt
index cc6682d..d4276b8 100644
--- a/rmq/main.rkt
+++ b/rmq/main.rkt
@@ -124,49 +124,55 @@
 
 (actor #:name 'hub
        (on (web-request-incoming (id req) vh 'post ("hub" ()) $body)
-           (actor*
-            #:name (gensym 'hub-post)
-            (define params (make-immutable-hash
-                            (form-urlencoded->alist (bytes->string/utf-8 body))))
-            (define callback (hash-ref params 'hub.callback))
-            (define mode
-              (match (hash-ref params 'hub.mode)
-                ["subscribe" 'subscribe]
-                ["unsubscribe" 'unsubscribe]))
-            (define topic (hash-ref params 'hub.topic))
-            (define lease-seconds
-              (match (hash-ref params 'hub.lease_seconds "unbounded")
-                ["unbounded" #f]
-                [n (string->number n)]))
-            (define secret-string (hash-ref params 'hub.secret #f))
-            (define secret-bytes (and secret-string (string->bytes/utf-8 secret-string)))
-            (define expiry-deadline (and lease-seconds (+ (current-seconds) lease-seconds)))
-            (define canonical-hub (url->string (resource->url (web-request-header-resource req))))
-            (define ok?
-              (match mode
-                ['subscribe
-                 (if (subscription-change-validate "subscribe"
-                                                   (or lease-seconds "unbounded")
-                                                   topic
-                                                   callback)
-                     (begin
-                       (retract! (subscription topic ? ? callback ?))
-                       (assert!
-                        (subscription topic expiry-deadline canonical-hub callback secret-bytes))
-                       #t)
-                     #f)]
-                ['unsubscribe
-                 (if (subscription-change-validate "unsubscribe"
-                                                   #f
-                                                   topic
-                                                   callback)
-                     (begin
-                       (retract! (subscription topic ? ? callback ?))
-                       #t)
-                     #f)]))
-            (if ok?
-                (web-respond/status! id 202 #"Accepted")
-                (web-respond/status! id 403 #"Forbidden" #"Validation failed"))))
+           ;; Initially, I had an (actor* ...) form here for fault
+           ;; isolation. However, this led to problems since I wanted
+           ;; to use `assert!` and `retract!` to signal to the
+           ;; `during/actor`, and the assertions were being lost as
+           ;; the `actor*` terminated. So instead, I'm using Rackety
+           ;; `with-handlers`.
+           (define ok?
+             (with-handlers [(values (lambda (e) #f))]
+               (define params (make-immutable-hash
+                               (form-urlencoded->alist (bytes->string/utf-8 body))))
+               (define callback (hash-ref params 'hub.callback))
+               (define mode
+                 (match (hash-ref params 'hub.mode)
+                   ["subscribe" 'subscribe]
+                   ["unsubscribe" 'unsubscribe]))
+               (define topic (hash-ref params 'hub.topic))
+               (define lease-seconds
+                 (match (hash-ref params 'hub.lease_seconds "unbounded")
+                   ["unbounded" #f]
+                   [n (string->number n)]))
+               (define secret-string (hash-ref params 'hub.secret #f))
+               (define secret-bytes (and secret-string (string->bytes/utf-8 secret-string)))
+               (define expiry-deadline (and lease-seconds (+ (current-seconds) lease-seconds)))
+               (define canonical-hub
+                 (url->string (resource->url (web-request-header-resource req))))
+               (match mode
+                 ['subscribe
+                  (if (subscription-change-validate "subscribe"
+                                                    (or lease-seconds "unbounded")
+                                                    topic
+                                                    callback)
+                      (begin
+                        (retract! (subscription topic ? ? callback ?))
+                        (assert!
+                         (subscription topic expiry-deadline canonical-hub callback secret-bytes))
+                        #t)
+                      #f)]
+                 ['unsubscribe
+                  (if (subscription-change-validate "unsubscribe"
+                                                    #f
+                                                    topic
+                                                    callback)
+                      (begin
+                        (retract! (subscription topic ? ? callback ?))
+                        #t)
+                      #f)])))
+           (if ok?
+               (web-respond/status! id 202 #"Accepted")
+               (web-respond/status! id 403 #"Forbidden" #"Validation failed")))
 
        (during/actor (subscription $topic _ _ $callback _)
                      #:name (list 'subscription topic callback)