If you are still experiencing this issue on sandbox. Ensure you visit the products section of your app Append the Login kit feature and add a redirect_uri,you have options to add more than 1 redirect_uris NB:Your authorization_url should look like this ? https://www.tiktok.com/v2/auth/auth...er-ui.vercel.app&state=9CZ7saUFzj3mJdTIAFhofA Continue reading...