Volkswagen has tightened access to its Connected services, forcing Home Assistant users to supply a client assertion before authentication. The move follows reports that the standard smartphone app and web portal still let drivers log in, but Home Assistant integrations fail with an “Anmeldung bei Volkswagen Connect nicht möglich” error. Users now see a dead‑end when the service claims credentials are expired in the past year for drivers.

The requirement stems from Volkswagen’s new security policy that mandates OAuth2 client assertions for all third‑party connections. Home Assistant, an open‑source platform that aggregates vehicle data, must now update its integration to supply a signed JSON Web Token. Until the patch rolls out, users can still log in through the official app but lose the automated data sync feature.

Developers of Home Assistant have released a temporary workaround that disables automatic token refresh, allowing users to manually re‑authenticate each session. The fix requires editing the integration’s configuration file and adding a static client ID. While this stops the immediate outage, it highlights the broader tension between automotive data access and evolving security standards.