diff --git a/src/proxy/middleware/response/index.ts b/src/proxy/middleware/response/index.ts
index a306737..6f4b408 100644
--- a/src/proxy/middleware/response/index.ts
+++ b/src/proxy/middleware/response/index.ts
@@ -187,8 +187,8 @@ const handleUpstreamErrors: ProxyResHandlerWithBody = async (
 
   const service = req.key!.service;
   if (service === "gcp") {
-    if (Array.isArray(errorPayload.error)) {
-      errorPayload.error = errorPayload.error[0];
+    if (Array.isArray(errorPayload)) {
+      errorPayload = errorPayload[0];
     }
   }