diff --git a/src/challenge-module/challenge-pin.hpp b/src/challenge-module/challenge-pin.hpp
index 88cf9bd..9e7d8b0 100644
--- a/src/challenge-module/challenge-pin.hpp
+++ b/src/challenge-module/challenge-pin.hpp
@@ -52,7 +52,7 @@
                const time::seconds& secretLifetime = time::seconds(3600));
 
   // For CA
-  std::tuple<Error, std::string>
+  std::tuple<ErrorCode, std::string>
   handleChallengeRequest(const Block& params, CertificateRequest& request) override;
 
   // For Client