diff --git a/apps/emqx_exhook/src/emqx_exhook_handler.erl b/apps/emqx_exhook/src/emqx_exhook_handler.erl
index eaf0cd0e0..bb2380e9b 100644
--- a/apps/emqx_exhook/src/emqx_exhook_handler.erl
+++ b/apps/emqx_exhook/src/emqx_exhook_handler.erl
@@ -269,8 +269,6 @@ message(#message{id = Id, qos = Qos, from = From, topic = Topic,
       headers => headers(Headers)
      }.
 
-headers(undefined) ->
-    #{};
 headers(Headers) ->
     Ls = [username, protocol, peerhost, allow_publish],
     maps:fold(