diff --git a/frontend/apps/remark42/app/common/api.ts b/frontend/apps/remark42/app/common/api.ts
index 717e8a69..81b0cab1 100644
--- a/frontend/apps/remark42/app/common/api.ts
+++ b/frontend/apps/remark42/app/common/api.ts
@@ -114,7 +114,7 @@ export const blockUser = (
   block: boolean;
   site_id: string;
   user_id: string;
-}> => adminFetcher.put(`/user/${id}`, { block: 1, ttl: ttl === 'permanently' ? ttl : undefined });
+}> => adminFetcher.put(`/user/${id}`, { block: 1, ttl: ttl === 'permanently' ? undefined : ttl });
 
 export const unblockUser = (
   id: User['id']