diff --git a/includes/api/ApiAuthManagerHelper.php b/includes/api/ApiAuthManagerHelper.php
index 5327d7a99bc..d037c365bdf 100644
--- a/includes/api/ApiAuthManagerHelper.php
+++ b/includes/api/ApiAuthManagerHelper.php
@@ -208,6 +208,7 @@ class ApiAuthManagerHelper {
 			$res->status === AuthenticationResponse::RESTART
 		) {
 			$this->formatMessage( $ret, 'message', $res->message );
+			$ret['messagecode'] = ApiMessage::create( $res->message )->getApiCode();
 		}
 
 		if ( $res->status === AuthenticationResponse::FAIL ||