diff --git a/CHANGELOG.md b/CHANGELOG.md
index 86e6a460..f30f4ec0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 Version XXX:
 
+* Fix logic error in advance_server_flex.
 * Fix file open with append_existing flag on posix.
 * Websocket SSL `teardown` also tears down underlying TCP.
 * Update WebSocket examples to set TLS SNI.
diff --git a/example/advanced/server-flex/advanced_server_flex.cpp b/example/advanced/server-flex/advanced_server_flex.cpp
index b0c889bf..70f2cb5a 100644
--- a/example/advanced/server-flex/advanced_server_flex.cpp
+++ b/example/advanced/server-flex/advanced_server_flex.cpp
@@ -321,7 +321,7 @@ class websocket_session
             return;
 
         if(ec)
-            fail(ec, "read");
+            return fail(ec, "read");
 
         // Echo the message
         derived().ws().text(derived().ws().got_text());