diff --git a/app/controllers/api/teams.php b/app/controllers/api/teams.php
index 8d0e76ac69..293bd7d112 100644
--- a/app/controllers/api/teams.php
+++ b/app/controllers/api/teams.php
@@ -627,8 +627,8 @@ App::patch('/v1/teams/:teamId/memberships/:membershipId/status')
             throw new Exception('Team IDs don\'t match', 404);
         }
 
-        if ($membership->getAttribute('confirm') !== false) {
-            throw new Exception('Membership already confirmed', 400);
+        if ($membership->getAttribute('confirm') === true) {
+            throw new Exception('Membership already confirmed', 409);
         }
 
         $team = Authorization::skip(fn() => $dbForProject->getDocument('teams', $teamId));