I ran into the same redirect issue, but in my case I was using WorkOS AuthKit + Next.js (App Router) deployed on AWS Amplify, not NextAuth. Posting this here since the root cause and fix are similar and might help others.

🧩 Problem
After a successful login, my app kept redirecting to https://localhost:3000/dashboard —even in production.
WorkOS was correctly configured with WORKOS_REDIRECT_URI=https:///callback,
but after the callback, the app itself issued a redirect to localhost.

⚙️ Root cause
@workos-inc/authkit-nextjs uses handleAuth() to manage the callback flow.
If you don’t provide a baseURL, it defaults to https://localhost:3000, which causes production redirects to break.

✅ Fix
Add this environment variable in Amplify (or your hosting platform):
NEXT_PUBLIC_URL=https://<<YOUR DOMAIN>>

Then update your /app/callback/route.ts:
import { handleAuth } from '@workos-inc/authkit-nextjs'; const baseURL = process.env.NEXT_PUBLIC_URL || 'http://localhost:3000'; export const GET = handleAuth({ baseURL }); export const POST = handleAuth({ baseURL, returnPathname: '/' });

Now WorkOS redirects correctly to your deployed domain.

✅ Summary:
If your Next.js app (using WorkOS, NextAuth, etc.) redirects to localhost after login,
set your baseURL explicitly — most auth kits default to localhost in the absence of one.