diff --git a/lib/util/http/github.ts b/lib/util/http/github.ts
index aacc666d7574c2bb98e14700404c83ec40b6f3c1..993b14cb62971534559381c59cc9c3ee47004ea8 100644
--- a/lib/util/http/github.ts
+++ b/lib/util/http/github.ts
@@ -1,4 +1,5 @@
 import URL from 'url';
+import is from '@sindresorhus/is';
 import pAll from 'p-all';
 import parseLinkHeader from 'parse-link-header';
 import {
@@ -43,8 +44,8 @@ function handleGotError(
 ): never {
   const path = url.toString();
   let message = err.message || '';
-  if (err.body?.message) {
-    message = err.body.message;
+  if (is.plainObject(err.response?.body) && 'message' in err.response.body) {
+    message = String(err.response.body.message);
   }
   if (
     err.name === 'RequestError' &&
@@ -114,7 +115,7 @@ function handleGotError(
     throw new ExternalHostError(err, PLATFORM_TYPE_GITHUB);
   }
   if (err.statusCode === 404) {
-    logger.debug({ url: err.options?.url }, 'GitHub 404');
+    logger.debug({ url: path }, 'GitHub 404');
   } else {
     logger.debug({ err }, 'Unknown GitHub error');
   }