diff --git a/example/advanced/server-flex-awaitable/advanced_server_flex_awaitable.cpp b/example/advanced/server-flex-awaitable/advanced_server_flex_awaitable.cpp
index fb3b8a54..a7e5b408 100644
--- a/example/advanced/server-flex-awaitable/advanced_server_flex_awaitable.cpp
+++ b/example/advanced/server-flex-awaitable/advanced_server_flex_awaitable.cpp
@@ -39,6 +39,7 @@
 #include <functional>
 #include <iostream>
 #include <memory>
+#include <list>
 #include <string>
 #include <thread>
 #include <vector>