diff --git a/packages/docs/src/service-worker.js b/packages/docs/src/service-worker.js
index 4f2c7f5761e..7a2b1575f16 100644
--- a/packages/docs/src/service-worker.js
+++ b/packages/docs/src/service-worker.js
@@ -89,6 +89,8 @@ async function matchPrecache (request) {
       response = ensureCacheableResponse(response)
       if (response.status === 200) {
         precache.put(cacheKey, response.clone())
+      } else {
+        console.error(`[SW] Failed to fetch missing precached asset ${request.url}`)
       }
     })
   }