diff --git a/lib/workers/repository/error.js b/lib/workers/repository/error.js
index af3cc637356a463a423fdd4f3bec15e3fd81281d..c75cba052a17c32fcdbcb7155dd38295ab165016 100644
--- a/lib/workers/repository/error.js
+++ b/lib/workers/repository/error.js
@@ -1,3 +1,4 @@
+const stringify = require('json-stringify-safe');
 const { raiseConfigWarningIssue } = require('./error-config');
 
 module.exports = {
@@ -47,24 +48,9 @@ async function handleError(config, err) {
   // Swallow this error so that other repositories can be processed
   logger.error(
     { err },
-    `Repository has unknown error:\n${stringifyError(err, null, '  ')}`
+    `Repository has unknown error:\n${stringify(err, null, 2)}`
   );
   // delete branchList to avoid cleaning up branches
   delete config.branchList; // eslint-disable-line no-param-reassign
   return 'unknown-error';
 }
-
-function stringifyError(err, filter, space) {
-  let stringifiedError = '';
-  try {
-    const plainObject = {};
-    Object.getOwnPropertyNames(err).forEach(key => {
-      plainObject[key] = err[key];
-    });
-    stringifiedError = JSON.stringify(plainObject, filter, space);
-  } catch (err2) {
-    // istanbul ignore next
-    logger.warn({ err2 }, 'Error stringifying unknown error');
-  }
-  return stringifiedError;
-}
diff --git a/package.json b/package.json
index 89cc1cec208fcb9bd39ceffefd37ce4443e3fd32..54d1da8b024b7adb50011d38e00d54f53f4f88c4 100644
--- a/package.json
+++ b/package.json
@@ -63,6 +63,7 @@
     "js-yaml": "3.10.0",
     "json-dup-key-validator": "1.0.2",
     "json-stringify-pretty-compact": "1.1.0",
+    "json-stringify-safe": "5.0.1",
     "later": "1.2.0",
     "lodash": "4.17.4",
     "minimatch": "3.0.4",
diff --git a/yarn.lock b/yarn.lock
index e3b674750454bd068b4ec693b6fbe92f17556f06..b6fe2fd165dc0e3bbb220225e1b77827cce832e5 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4034,7 +4034,7 @@ json-stringify-pretty-compact@1.1.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/json-stringify-pretty-compact/-/json-stringify-pretty-compact-1.1.0.tgz#4fa5b898f61a287d64828691baa822a41f3ad5ab"
 
-json-stringify-safe@^5.0.1, json-stringify-safe@~5.0.1:
+json-stringify-safe@5.0.1, json-stringify-safe@^5.0.1, json-stringify-safe@~5.0.1:
   version "5.0.1"
   resolved "https://registry.yarnpkg.com/json-stringify-safe/-/json-stringify-safe-5.0.1.tgz#1296a2d58fd45f19a0f6ce01d65701e2c735b6eb"