diff --git a/src/Network/GemServ.hs b/src/Network/GemServ.hs
index 12e81a0..64b7263 100644
--- a/src/Network/GemServ.hs
+++ b/src/Network/GemServ.hs
@@ -197,12 +197,13 @@ adjustServerParams certRef params = let
   hooks    = serverHooks params
   certHook = onClientCertificate hooks
 
-  certHook' chain = case chain of
-    CertificateChain []     -> certHook chain
-    CertificateChain (se:_) -> do
-      let cert = signedObject $ getSigned se
-      writeIORef certRef (Just cert)
-      certHook chain
+  certHook' chain = do
+    case chain of
+      CertificateChain []     -> return ()
+      CertificateChain (se:_) -> do
+        let cert = signedObject $ getSigned se
+        writeIORef certRef (Just cert)
+    certHook chain
 
   hooks' = hooks { onClientCertificate = certHook' }
   in params { serverHooks = hooks' }