diff --git a/tools/ndn-autoconfig/multicast-discovery.cpp b/tools/ndn-autoconfig/multicast-discovery.cpp
index c1ec0c5..d9eeeb3 100644
--- a/tools/ndn-autoconfig/multicast-discovery.cpp
+++ b/tools/ndn-autoconfig/multicast-discovery.cpp
@@ -147,11 +147,12 @@
 
   m_face.expressInterest(interest,
                          bind(&MulticastDiscovery::onSuccess, this, _2),
-                         bind(m_nextStageOnFailure, "Timeout"));
+                         bind(m_nextStageOnFailure, "HUB Data not received: nacked"),
+                         bind(m_nextStageOnFailure, "HUB Data not received: timeout"));
 }
 
 void
-MulticastDiscovery::onSuccess(Data& data)
+MulticastDiscovery::onSuccess(const Data& data)
 {
   const Block& content = data.getContent();
   content.parse();
diff --git a/tools/ndn-autoconfig/multicast-discovery.hpp b/tools/ndn-autoconfig/multicast-discovery.hpp
index 5d03e43..13d8c36 100644
--- a/tools/ndn-autoconfig/multicast-discovery.hpp
+++ b/tools/ndn-autoconfig/multicast-discovery.hpp
@@ -56,7 +56,7 @@
    */
   MulticastDiscovery(Face& face, KeyChain& keyChain, const NextStageCallback& nextStageOnFailure);
 
-  virtual void
+  void
   start() override;
 
 private:
@@ -83,7 +83,7 @@
   requestHubData();
 
   void
-  onSuccess(Data& data);
+  onSuccess(const Data& data);
 
 private:
   size_t m_nRequestedRegs;