diff --git a/main.fnl b/main.fnl
index 886cc69..21f0a82 100644
--- a/main.fnl
+++ b/main.fnl
@@ -94,10 +94,11 @@
     (crt:toPEM)))
 
 (fn approve-request? [csr]
-  (let [attr (csr:getAttributes)]
-    (accumulate [found false
-                 _ v (ipairs (. attr "challengePassword"))]
-      (or found (= v options.challenge-password)))))
+  (let [{ : challengePassword } (csr:getAttributes)]
+    (when challengePassword
+      (accumulate [found false
+                   _ v (ipairs challengePassword)]
+        (or found (= v options.challenge-password))))))
 
 (fn handle-sign-csr [out]
   (let [req (csr.new (out:get_body_as_string))]