diff --git a/cpp/core_v2/internal/bwu_manager.cc b/cpp/core_v2/internal/bwu_manager.cc
index 135a21e9..63efd9ec 100644
--- a/cpp/core_v2/internal/bwu_manager.cc
+++ b/cpp/core_v2/internal/bwu_manager.cc
@@ -721,7 +721,7 @@ Medium BwuManager::ChooseBestUpgradeMedium(const std::vector<Medium>& mediums) {
     // switch.
     NEARBY_LOG(
         INFO,
-        "Current upgrade medium %s is not supported by the remote endpoint",
+        "Current upgrade medium %d is not supported by the remote endpoint",
         medium_);
   }