diff --git a/interface.php b/interface.php
index 1f85cac..b3062d5 100644
--- a/interface.php
+++ b/interface.php
@@ -539,7 +539,7 @@ function generate_report_by_groups(ReqHandler &$rh, array $params): string
     $game = $gameMgr->getGame($gameid);
 
     // verify game and access
-    if (($game === null) || (!$game->isUserContributorOrOwner($user->getNickname()) || $user->hasQuizmasterPrivilege())) {
+    if (($game === null) || (!$game->isUserContributorOrOwner($user->getNickname()) || !$user->hasQuizmasterPrivilege())) {
         return "FAIL";
     }