diff --git a/web/panettone/src/authentication.lisp b/web/panettone/src/authentication.lisp
index 205102575..50befbc7a 100644
--- a/web/panettone/src/authentication.lisp
+++ b/web/panettone/src/authentication.lisp
@@ -79,12 +79,18 @@ and a retry"
 
 (defun find-user-by-dn (dn)
   (with-ldap ()
-    (progn
-      (ldap:search *ldap* `(= objectClass organizationalPerson)
-                   :base dn
-                   :scope 'ldap:base)
-      (when-let ((ldap-entry (ldap:next-search-result *ldap*)))
-        (ldap-entry->user ldap-entry)))))
+    (let ((have-results
+            (handler-case
+              (ldap:search *ldap* `(= objectClass organizationalPerson)
+                           :base dn
+                           :scope 'ldap:base)
+              ; catch ldap-errors generated by trivial-ldap:parse-ldap-message
+              ; since this is thrown on conditions which we don't want this
+              ; function to fail like when there are no search results
+              (trivial-ldap:ldap-error (e) nil))))
+      (when have-results
+        (when-let ((ldap-entry (ldap:next-search-result *ldap*)))
+          (ldap-entry->user ldap-entry))))))
 
 (comment
  (find-user-by-dn "cn=glittershark,ou=users,dc=tvl,dc=fyi")
diff --git a/web/panettone/src/panettone.lisp b/web/panettone/src/panettone.lisp
index e090f11ac..6e4331232 100644
--- a/web/panettone/src/panettone.lisp
+++ b/web/panettone/src/panettone.lisp
@@ -90,6 +90,10 @@
 (defun author (object)
   (find-user-by-dn (author-dn object)))
 
+(defun displayname-if-known (user)
+  (or (when user (displayname user))
+      "unknown"))
+
 (defmacro render ((&key
                      (footer t)
                      (header t))
@@ -171,11 +175,8 @@
     (:span :class "created-by-at"
            "Opened by "
            (:span :class "username"
-                  (who:esc
-                   (or
-                    (when-let ((author (author issue)))
-                      (displayname author))
-                    "someone")))
+                  (who:esc (displayname-if-known
+                             (author issue))))
            " at "
            (:span :class "timestamp"
                   (who:esc
@@ -293,7 +294,8 @@
        (:p
         :class "comment-info"
         (:span :class "username"
-               (who:esc (displayname (author comment)))
+               (who:esc
+                 (displayname-if-known (author comment)))
                " at "
                (:a :href (concatenate 'string "#" fragment)
                    (who:esc (format-dottime (created-at comment))))))))))
@@ -304,7 +306,7 @@
       (:li
        :class "event"
        :id
-       (who:esc (displayname user))
+       (who:esc (displayname-if-known user))
        (if (string= (field event) "STATUS")
            (who:htm
             (who:esc