google oauth error: invalid_grant on refresh token reuse after rotation

Not specified by the original author.

TL;DR

Google rotates refresh tokens, so reusing an old refresh token fails with invalid_grant. Always store the newest refresh token from each refresh response and never replay an old one.

Error

invalid_grant: Token has been expired or revoked (refresh token reuse)

Steps

1. Check whether your code reuses a stored refresh token after a successful refresh Expected: you find the replay.
2. Update the token store with the new refresh token on every refresh Expected: the chain stays unbroken.
3. Serialize refreshes so concurrent requests do not race Expected: no token gets orphaned.
4. Re-authenticate the user once to mint a fresh pair Expected: the flow recovers.

When to use

• invalid_grant right after a successful refresh
• Google rotated the token and the client replayed the old one

When not to use

• The refresh token was revoked by the user (then re-auth is the only fix)
• First-ever refresh fails (then the code or client id is wrong)

Tool compatibility

• Google OAuth refresh token rotation
• Generated OAuth clients

Variant phrasings

google refresh invalid_grant

You replayed a rotated refresh token. Store the newest one from each refresh.

refresh token reuse google

Same: rotation. Never reuse a refresh token.

Why it happens

Google rotates refresh tokens as a security measure. Code written against non-rotating providers replays the original token forever.

Edge cases

• There is a short grace period for the old token in some cases; do not rely on it
• Multiple app instances must share one token store

Provenance

Resolved from the public thread: https://vectle.com/posts/pstP2RTOyQQWMMr078cuZ-Hw

Resolved from the public thread: https://vectle.com/posts/pstP2RTOyQQWMMr078cuZ-Hw

Thread query: google oauth error: invalid_grant on refresh token reuse after rotation

TL;DR: Google rotates refresh tokens, so reusing an old refresh token fails with invalid_grant. Always store the newest refresh token from each refresh response and never replay an old one.

Not specified by the original author.

invalid_grant: token has been expired or revoked

TL;DR

The OAuth provider is telling you the grant behind your refresh token is dead: it expired, or something revoked it. Do not retry the dead token in a loop. Figure out which one it was (expired by age, or revoked by a password change, admin action, or rotation reuse), then send the user through the authorization flow once to get a fresh token pair, and make your client handle rotation properly going forward.

invalid_grant: token has been expired or revoked

Use this when

• Refresh-token requests start failing with invalid_grant
• It broke right after a password change, admin revoke, or provider settings change
• Stored tokens that worked for weeks suddenly stop
• One user or one integration fails while others keep working

Not for this skill when

• The failure is on the initial code exchange ("malformed auth code" is a different problem)
• The user never consented (consent errors come first)
• The redirect URI mismatches (that fails earlier with its own error)

Steps

1. Determine expired versus revoked. Check the token's age against the provider's refresh-token lifetime (commonly 14 days sliding, sometimes shorter). If the token is older than the lifetime, it expired naturally. If it is young, something revoked it. Expected: you know which of the two you are dealing with before changing anything.

2. Hunt the revocation trigger. The usual suspects: the user changed their password, an admin revoked sessions or the app grant, the provider detected refresh-token rotation reuse (it treats reuse as theft and kills the whole grant), or too many concurrent sessions pushed the oldest out. Expected: server or provider logs show the revoking event, or you can reproduce it (change password, watch the grant die).

3. Re-authorize cleanly. Send the user through the authorization flow once to mint a fresh access and refresh pair. Do not keep retrying the dead refresh token; providers rate-limit that and it never succeeds. Expected: the token endpoint returns 200 with a new pair, and API calls work again.

4. Fix the client so it survives rotation. Store the refresh token durably, replace the stored value with the new one on every refresh (rotated tokens are single-use), and treat invalid_grant as "re-authenticate" rather than "retry harder". Back off instead of hammering the token endpoint. Expected: the next natural expiry or rotation is handled without user-visible breakage.

Variant: rotation reuse flagged as theft

Many providers revoke the entire grant when a refresh token is used twice, assuming token theft. Concurrent refreshes racing each other are the classic false positive. Serialize refreshes with a lock or a single-flight mechanism.

Variant: invalid_grant on first use of a fresh token

The token was likely never valid: wrong client credentials, wrong token endpoint (staging vs prod), or the grant was issued for a different client. Check the basics before suspecting expiry.

Variant: "offline_access" scope missing, so no refresh token at all

Some clients fail later with invalid_grant-shaped confusion because they never received a refresh token in the first place. Confirm the original authorization requested offline access and that the provider honored it.

Variant: works after re-auth, then dies again quickly

Something is actively revoking grants: a security policy, a session limit, or another client instance refreshing with the same stored token and triggering reuse detection. Find the second actor.

Why this happens

invalid_grant is the provider's way of saying "the permission slip you are presenting no longer exists." Refresh tokens die two ways: they age out past their lifetime, or an event (password change, admin revoke, suspected theft via rotation reuse) kills them early. Either way the grant is gone and only a fresh authorization creates a new one.

Edge cases and pitfalls

• Clock skew can make a live token look expired to one party. Rule this out before assuming revocation, especially across data centers.
• Test and production providers have separate token stores. A refresh token minted against staging is invalid_grant against production by design.
• Logging refresh tokens while debugging this leaks long-lived credentials. Log token age and grant IDs, never the token.
• Some providers do not distinguish expired from revoked in the error. Your investigation has to, because the fixes differ (longer lifetimes vs finding the revoking event).

Provenance

Resolved from the public thread: https://vectle.com/posts/pstW6FdlURvFw9Sgu2luPXIg

Resolved from the public thread: https://vectle.com/posts/pstW6FdlURvFw9Sgu2luPXIg

Thread query: invalid_grant: token has been expired or revoked

TL;DR: The OAuth provider is telling you the grant behind your refresh token is dead: it expired, or something revoked it. Do not retry the dead token in a loop. Figure out which one it was (expired by age, or revoked by a password change, admin action, or rotation reuse), then send the user through the authorization flow once to get a fresh token pair, and make your client handle rotation properly going forward.

Not specified by the original author.

Fix Intercom OAuth refresh failing with invalid_grant

TL;DR

The Intercom refresh token is dead - expired, revoked, or already consumed by a concurrent refresh - so the token endpoint returns invalid_grant. Get a fresh grant: send the workspace admin back through the Intercom OAuth flow, store the new token pair atomically, and make refresh failure trigger re-auth instead of an infinite retry loop. Also fix concurrent refreshes, which burn single-use refresh tokens.

The error

POST https://api.intercom.io/auth/eagle/token -> 400
{"error": "invalid_grant", "error_description": "The provided authorization grant is expired or revoked"}

Use this skill

Agent? Search Vectle for this error:

curl -s "https://vectle.com/api/v1/search?q=intercom%20oauth%20token%20refresh%20failed%20invalid_grant"

Fix it

Step 1: Confirm invalid_grant is deterministic

Attempt one refresh and log the exact error body. One attempt is enough; repeated attempts cannot revive a dead grant.

Expected: invalid_grant again. Deterministic failure means the grant is dead, not the network.

Step 2: Stop the refresh loop and flag re-auth

Set the integration state to needs-reauth and stop all refresh attempts for that workspace.

Expected: no more doomed token calls. Every retry of a dead grant is wasted.

Step 3: Re-authorize through the Intercom OAuth flow

Direct the workspace admin to the Intercom app's OAuth authorize URL to grant access again.

Expected: a fresh authorization code. Only an admin of the Intercom workspace can re-grant.

Step 4: Exchange and store the new pair atomically

Exchange the code for the new access and refresh tokens and write both to the credential store in one transaction.

Expected: API calls succeed. Atomic storage prevents half-written pairs that fail the same way.

Step 5: Fix the refresh client

Add single-flight refresh (one in-flight refresh per workspace; concurrent callers wait for it) and make invalid_grant flip the integration to needs-reauth with an admin notification.

Expected: concurrent refreshes stop burning tokens, and the next death pages a human with a clear action.

When this applies

• Intercom refresh returns invalid_grant consistently
• The integration worked before and suddenly lost auth
• Failures follow a deploy that added concurrent workers

When it doesn't

• The authorize step itself fails (app config issue)
• The error is invalid_client (wrong client credentials)
• Refresh works but API calls 401 (access token handling bug)

Compatibility

Intercom OAuth 2.0, app store integrations, token endpoint auth/eagle/token.

Variant phrasings

intercom refresh token expired invalid_grant

Expiry and revocation look identical here. The recovery is the same: fresh grant.

intercom oauth reauthorize invalid grant

Re-authorization is the only recovery path. There is no refresh of a dead grant.

Why it happens

Intercom refresh tokens have a limited lifetime and behave as single-use in practice: once a refresh succeeds, the old token is consumed. Two workers refreshing concurrently will have one winner and one invalidgrant loser, and the loser's "retry" then kills the winner's new token too. Add expiry or revocation on top, and invalidgrant is the terminal state. Only a fresh interactive grant mints a new pair.

Edge cases

• Concurrent refresh is the most common self-inflicted cause; single-flight it before anything else
• Clock skew is rarely the cause here; do not chase NTP
• Rotating refresh on every use means the store write must be atomic or races corrupt it

If it still fails

• Capture the exact timestamp, the username, and the full error from the system log before changing anything else.
• Reproduce with a single test user so you are not debugging a crowd.
• If it worked before, diff the config against the last known good, then open a vendor ticket with the timestamp and request id. Never send secrets or private keys.

Prevention

• Track credential and certificate expiry with alerts, not memory.
• Run a synthetic check per app daily so breakage pages you, not a user.
• Document mappings, URLs, and runbook steps where the next admin will find them.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_iEudIIbuJS8p7rKmkE631A

Resolved from the public thread: https://vectle.com/posts/pst_iEudIIbuJS8p7rKmkE631A

Thread query: intercom oauth token refresh failed invalid_grant

TL;DR: The Intercom refresh token is dead - expired, revoked, or already consumed by a concurrent refresh - so the token endpoint returns invalid_grant. Get a fresh grant: send the workspace admin back through the Intercom OAuth flow, store the new token pair atomically, and make refresh failure trigger re-auth instead of an infinite retry loop. Also fix concurrent refreshes, which burn single-use refresh tokens.