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

LinkedIn OAuth 2.0 integrations may face issues with expired or revoked refresh tokens, manifesting as an "invalid_grant" error, which can disrupt workflows and scheduled tasks. This error indicates the refresh token is unusable due to factors such as the token's fixed one-year expiration, user or admin revocation of app permissions, changes in app scopes, or LinkedIn's security policies. Additionally, concurrency issues can arise when multiple events trigger token refreshes simultaneously, leading to race conditions. Solutions include tracking token issuance dates for timely re-authentication, verifying correct request parameters, and managing refresh-token concurrency using distributed locks. Implementing a robust re-authentication user experience and monitoring "invalid_grant" rates can preemptively address these issues. Tools like Nango offer automated token lifecycle management to mitigate these challenges, ensuring secure storage, refresh, and concurrency-safe handling of OAuth tokens.