diff --git a/tools/ndncert-ca-server.cpp b/tools/ndncert-ca-server.cpp
index 232c0d9..57493e9 100644
--- a/tools/ndncert-ca-server.cpp
+++ b/tools/ndncert-ca-server.cpp
@@ -19,7 +19,7 @@
  */
 
 #include "ca-module.hpp"
-#include "challenge-module.hpp"
+#include "identity-challenge/challenge-module.hpp"
 #include <ndn-cxx/face.hpp>
 #include <ndn-cxx/security/key-chain.hpp>
 #include <boost/asio.hpp>