LinkedIn OAuth refresh token invalid_grant — What it means & how to fix it

LinkedIn's OAuth 2.0 integration can encounter "invalid_grant" errors during token refresh, leading to disruptions in scheduled syncs, background jobs, or user-triggered actions. This issue arises when the refresh token becomes expired or revoked, which can be due to several reasons such as fixed token lifetimes, user or admin actions, changes in app permissions, or LinkedIn's policy decisions. To address this, it is essential to track the token issuance time and prompt re-authentication before expiration, verify refresh request accuracy, and manage refresh concurrency using locking mechanisms. Employing tools like Nango can streamline this process by handling token lifecycle management, ensuring safe token refreshes without race conditions, and providing clear re-authentication signals. Adopting these strategies can minimize integration failures and enhance user experience by maintaining a consistent LinkedIn connection.