diff --git a/src/Trading/Services/TradingBaseService.php b/src/Trading/Services/TradingBaseService.php
index 52d1811e32..1a962ad936 100644
--- a/src/Trading/Services/TradingBaseService.php
+++ b/src/Trading/Services/TradingBaseService.php
@@ -160,7 +160,7 @@ protected function getEbayHeaders($operationName)
          * Note that we have no way of detecting that the actual request has an attachment.
          */
         if ($operationName === 'UploadSiteHostedPictures') {
-            $headers['Content-Type'] = 'multipart/form-data;boundary="boundary"';
+            $headers['Content-Type'] = 'multipart/form-data;boundary=boundary';
         }
 
         return $headers;