diff --git a/src/storage/gcs.js b/src/storage/gcs.js
index 1bf915e93..19055873e 100644
--- a/src/storage/gcs.js
+++ b/src/storage/gcs.js
@@ -256,7 +256,7 @@ async function verifyConfig({ id, provider, config }) {
     const uploadStream = testFile.createWriteStream({ resumable: false });
 
     await new Promise((resolve, reject) => {
-        uploadStream.on('error', function(error) {
+        uploadStream.on('error', (error) => {
             debug('testConfig: failed uploading cloudron-testfile. %o', error);
             if (error && error.code && (error.code == 403 || error.code == 404)) {
                 return reject(new BoxError(BoxError.BAD_FIELD, error.message));
@@ -264,10 +264,8 @@ async function verifyConfig({ id, provider, config }) {
 
             return reject(new BoxError(BoxError.EXTERNAL_ERROR, error.message));
         });
-        uploadStream.write('testfilecontents');
-        uploadStream.end();
-
         uploadStream.on('finish', resolve);
+        uploadStream.end('testfilecontents');
     });
     debug('testConfig: uploaded cloudron-testfile');