Callback handler missing state parameter (vercel)

Help
,
1

tl;dr;
I can’t make to work an application in vercel where I use subdomain for multi tenant. Is there an example app where this is done? It’s correct to pass the Auth0 api routes (/api/auth0/login, etc.) through edge middleware?

I have a multi tenant application and I use edge middleware to support it via subdomains, this is the middleware relevant code:

//middleware.js
...
const account =
   process.env.NODE_ENV === "production" && process.env.VERCEL === "1"
      ? hostname.split('.')[0]
      : hostname.replace(`.localhost:3000`, "");

if (req.nextUrl.pathname.startsWith('/api')) {
   return NextResponse.rewrite(
      new URL(`/api/${account}${req.nextUrl.pathname.replace('/api', '')}`, req.url)
   );
}
...

I’m using a custom auth0 handler to set a valid baseURL because a fixed one as env variable displays a different error (invalid_grant) :

   const baseURL = `${process.env.NODE_ENV === "development"
      || (req.headers.host?.indexOf('localhost') || -1) >= 0 ? "http" : "https"}://${req.headers.host
      }`
   return initAuth0({
      baseURL,
      secret: process.env.AUTH0_SECRET,
      issuerBaseURL: process.env.AUTH0_ISSUER_BASE_URL,
      clientID: process.env.AUTH0_CLIENT_ID,
      clientSecret: process.env.AUTH0_CLIENT_SECRET
   });

in my local the login process works fine, but when I deploy to vercel I get an error in this route: http://org.example.com/api/auth/callback it says:

CallbackHandlerError: Callback handler failed. CAUSE: Missing state parameter in Authorization Response.

but both, code an state parameters are present in the url, I can’t help but thinking that something about the middleware is causing the error

3

Hey team!

This topic seems related to the new Auth0 Integration available new in Vercel Marketplace. This is the first version of this integration, and we welcome your feedback to improve future iterations.

You’ll need an existing Vercel project to use the new integration to build and customize the Identity flow. You can either import your project into Vercel or use a Vercel template so you don’t have to start from scratch like our SaaStart template to deploy a production-ready B2B SaaS app in minutes (learn more here).

If you find yourself having questions regarding this new integration for the next two weeks, we are hosting an Ask Me Anything session. Our Product Expert will provide comprehensive written answers on August 8th from 8 AM to 10 AM PST.

Find out more about Auth0 Integration and learn more about AMA.

Thanks!
Dawid