diff --git a/src/controllers/episodes/markEpisodeAsWatched/index.ts b/src/controllers/episodes/markEpisodeAsWatched/index.ts
index 91a581a..d8a707b 100644
--- a/src/controllers/episodes/markEpisodeAsWatched/index.ts
+++ b/src/controllers/episodes/markEpisodeAsWatched/index.ts
@@ -72,7 +72,7 @@ app.openapi(route, async (c) => {
     return c.json(ErrorResponse, { status: 401 });
   }
 
-  const deviceId = c.req.header("X-Aniplay-DeviceId")!;
+  const deviceId = c.req.header("X-Aniplay-Device-Id")!;
   const aniListId = Number(c.req.param("aniListId"));
   const { episodeNumber, isComplete } =
     await c.req.json<typeof MarkEpisodeAsWatchedRequest._type>();