diff --git a/src/Composer/Console/Application.php b/src/Composer/Console/Application.php
index f1d5d9ffb..2f3e2c4b1 100644
--- a/src/Composer/Console/Application.php
+++ b/src/Composer/Console/Application.php
@@ -446,6 +446,7 @@ class Application extends BaseApplication
             // as http error codes are all beyond the 255 range of permitted exit codes
             if ($e instanceof TransportException) {
                 $reflProp = new \ReflectionProperty($e, 'code');
+                $reflProp->setAccessible(true);
                 $reflProp->setValue($e, Installer::ERROR_TRANSPORT_EXCEPTION);
             }