diff --git a/app/api/chat/route.ts b/app/api/chat/route.ts
index b39b26c..594925c 100644
--- a/app/api/chat/route.ts
+++ b/app/api/chat/route.ts
@@ -18,10 +18,10 @@ export async function POST(req: Request) {
   const { messages, previewToken } = json
   const session = await auth()
 
-  if (process.env.VERCEL_ENV === 'preview') {
-    if (session == null) {
-      return new Response('Unauthorized', { status: 401 })
-    }
+  if (session == null) {
+    return new Response('Unauthorized', {
+      status: 401
+    })
   }
 
   if (previewToken) {
diff --git a/app/sign-in/page.tsx b/app/sign-in/page.tsx
index 00891e7..280333e 100644
--- a/app/sign-in/page.tsx
+++ b/app/sign-in/page.tsx
@@ -1,6 +1,13 @@
+import { auth } from '@/auth'
 import { LoginButton } from '@/components/login-button'
+import { redirect } from 'next/navigation'
 
-export default function SignInPage() {
+export default async function SignInPage() {
+  const session = await auth()
+  // redirect to home if user is already logged in
+  if (session?.user) {
+    redirect('/')
+  }
   return (
     <div className="flex h-[calc(100vh-theme(spacing.16))] items-center justify-center py-10">
       <LoginButton />
diff --git a/auth.ts b/auth.ts
index 5c7c1dd..c6562d5 100644
--- a/auth.ts
+++ b/auth.ts
@@ -17,11 +17,11 @@ export const {
         token.image = profile.picture
       }
       return token
+    },
+    // @ts-ignore
+    authorized({ auth }) {
+      return !!auth?.user
     }
-    // @TODO
-    // authorized({ request, auth }) {
-    //   return !!auth?.user
-    // }
   },
   pages: {
     signIn: '/sign-in'
diff --git a/components/chat.tsx b/components/chat.tsx
index b3a8394..a9ecafe 100644
--- a/components/chat.tsx
+++ b/components/chat.tsx
@@ -19,6 +19,7 @@ import {
 import { useState } from 'react'
 import { Button } from './ui/button'
 import { Input } from './ui/input'
+import { toast } from 'react-hot-toast'
 
 const IS_PREVIEW = process.env.VERCEL_ENV === 'preview'
 export interface ChatProps extends React.ComponentProps<'div'> {
@@ -40,6 +41,11 @@ export function Chat({ id, initialMessages, className }: ChatProps) {
       body: {
         id,
         previewToken
+      },
+      onResponse(response) {
+        if (response.status === 401) {
+          toast.error(response.statusText)
+        }
       }
     })
   return (
diff --git a/middleware.ts b/middleware.ts
index 4afe145..d70f753 100644
--- a/middleware.ts
+++ b/middleware.ts
@@ -1 +1,5 @@
 export { auth as middleware } from './auth'
+
+export const config = {
+  matcher: ['/', '/api/chat']
+}