diff --git a/lib/manager/bundler/artifacts.js b/lib/manager/bundler/artifacts.js
index 57e38f37d32e2b295de26964ab80b7d2a7216907..3dd62193614d0390aae6db1db002e4bf300b305e 100644
--- a/lib/manager/bundler/artifacts.js
+++ b/lib/manager/bundler/artifacts.js
@@ -166,8 +166,9 @@ async function getArtifacts(
       throw new Error('bundler-fs');
     }
     if (
-      err.stdout &&
-      err.stdout.includes('Please supply credentials for this source')
+      (err.stdout &&
+        err.stdout.includes('Please supply credentials for this source')) ||
+      (err.stderr && err.stderr.includes('Authentication is required'))
     ) {
       logger.warn(
         { err },