diff --git a/server.go b/server.go
index f441da4..1f95e33 100644
--- a/server.go
+++ b/server.go
@@ -24,7 +24,7 @@ import (
 )
 
 const (
-	CookieKeyIDMeshUserID = "IDMesh-User-Id"
+	CookieKeyIDMeshUserID = "idmesh_user_id"
 )
 
 type Config struct {