Error 401 on fresh install

Hi,
One of my client just installed my app.
My app is based on old remix.run template (before merge with react-router) and is working on:
“@remix-runremix-run/fs-routes”: “^2@remix-run17.2”,
“@remix-run/n@remix-runde”: “^2.17.2”,
“@rem@remix-runx-run/react”: “^2.17.2”,
“@remix-run/@remix-runoutes-option-adapter”: “^2.17.2”,
“@remix-run/serve”: “^2.17.2”,
@shopify/shopify-app-remix”: “4.0.6”,
@shopify/shopify-app-session-storage-prisma”: “7.0.3”,

But keep getting an error 401 after validating the app install, when the user is redirected to /app.

Before everything was working, as my app was validated.
But now i got this strange erreror.
The session is existing in the database, and the access_token is working.
I tried this to confirm:
curl -X GET “``https://XXXXX.myshopify.com/admin/api/2024-10/shop.json”
-H “X-Shopify-Access-Token: shpat_XXXXXXXX”
and I got a 200 answer.

The problem is coming from `authentification.admin()` function.
I’m getting those logs:

Authentication failed: Response {

2025-12-04T15:14:19.767802879Z   status: 401,

2025-12-04T15:14:19.767805854Z   statusText: ‘Unauthorized’,

2025-12-04T15:14:19.767807978Z   headers: Headers { ‘X-Shopify-Retry-Invalid-Session-Request’: ‘1’ },

2025-12-04T15:14:19.767810052Z   body: null,

2025-12-04T15:14:19.767811856Z   bodyUsed: false,

2025-12-04T15:14:19.767813759Z   ok: false,

2025-12-04T15:14:19.767815362Z   redirected: false,

2025-12-04T15:14:19.767817176Z   type: ‘default’,

2025-12-04T15:14:19.767818819Z   url: ‘’

2025-12-04T15:14:19.767820482Z }

But in the log i can clearly see:
[shopify-app/INFO] Authenticating admin request | {shop: ``XXXXX.myshopify.com``}

Is anyone facing the same problem ?

error was:
"nbf" claim timestamp check failed

Because my server was 24 second behind…

Got this error by activating log in shopify.server.ts, good to know