adds a custom redirect callback that also let's urls with origin WEBSITE-URL (app.cal.com) pass, otherwise redirected to cal.com instead of app.cal.com on callback

apps/web/pages/api/auth/[...nextauth].tsx

@@ -434,5 +434,12 @@ export default NextAuth({
 
       return false;
     },
+    async redirect({ url, baseUrl }) {
+      // Allows relative callback URLs
+      if (url.startsWith("/")) return `${baseUrl}${url}`;
+      // Allows callback URLs on the same origin
+      else if (new URL(url).origin === baseUrl || WEBSITE_URL) return url;
+      return baseUrl;
+    },
   },
 });