...

src/app/folders/[folder_id]/page.tsx

@@ -17,7 +17,7 @@ export default async function FoldersPage({
     redirect("/folders");
   }
   if (!session) redirect(`/login?redirect=/folders/${folder_id}`);
-  if ((await getUserIdByFolderId(folder_id)) !== session.user.id) {
+  if ((await getUserIdByFolderId(Number(folder_id))) !== session.user.id) {
     return <p>{t("unauthorized")}</p>;
   }
   return <InFolder folderId={Number(folder_id)} />;

src/app/folders/page.tsx

@@ -2,6 +2,7 @@ import { auth } from "@/auth";
 import FoldersClient from "./FoldersClient";
 import { redirect } from "next/navigation";
 import { headers } from "next/headers";
+
 export default async function FoldersPage() {
   const session = await auth.api.getSession(
     { headers: await headers() }