diff --git a/redfish-core/include/error_messages.hpp b/redfish-core/include/error_messages.hpp
index 9b35e6d..ed00447 100644
--- a/redfish-core/include/error_messages.hpp
+++ b/redfish-core/include/error_messages.hpp
@@ -425,6 +425,22 @@
                                    const boost::urls::url_view& arg3);
 
 /**
+ * @brief Formats PropertyValueExternalConflict message into JSON
+ * Message body: "The property '%1' with the requested value of '%2' could not
+ * be written because the value is not available due to a configuration
+ * conflict."
+ *
+ * @param[in] arg1 Parameter of message that will replace %1 in its body.
+ * @param[in] arg2 Parameter of message that will replace %2 in its body.
+ *
+ * @returns Message PropertyValueExternalConflict formatted to JSON */
+nlohmann::json propertyValueExternalConflict(std::string_view arg1,
+                                             std::string_view arg2);
+
+void propertyValueExternalConflict(crow::Response& res, std::string_view arg1,
+                                   std::string_view arg2);
+
+/**
  * @brief Formats PropertyValueIncorrect message into JSON
  * Message body: "The property '<arg1>' with the requested value of '<arg2>'
  * could not be written because the value does not meet the constraints of the
diff --git a/redfish-core/src/error_messages.cpp b/redfish-core/src/error_messages.cpp
index 8f8b00b..5c4fb31 100644
--- a/redfish-core/src/error_messages.cpp
+++ b/redfish-core/src/error_messages.cpp
@@ -756,6 +756,29 @@
 
 /**
  * @internal
+ * @brief Formats PropertyValueExternalConflict message into JSON
+ *
+ * See header file for more information
+ * @endinternal
+ */
+nlohmann::json propertyValueExternalConflict(std::string_view arg1,
+                                             std::string_view arg2)
+{
+    return getLog(
+        redfish::registries::base::Index::propertyValueExternalConflict,
+        std::to_array({arg1, arg2}));
+}
+
+void propertyValueExternalConflict(crow::Response& res, std::string_view arg1,
+                                   std::string_view arg2)
+{
+    res.result(boost::beast::http::status::conflict);
+    addMessageToErrorJson(res.jsonValue,
+                          propertyValueExternalConflict(arg1, arg2));
+}
+
+/**
+ * @internal
  * @brief Formats PropertyValueIncorrect message into JSON
  *
  * See header file for more information