What Causes the QuickBooks invalid_grant Error?
An [.inline-code-highlight]invalid_grant[.inline-code-highlight] error may happen during the OAuth 2.0 authentication flow for QuickBooks during the access (bearer) token request or the token refresh request.
When retrieving the access token, this error may happen because:
- An incorrect redirect URI was specified in the request
- An incorrect OAuth 2.0 key was used
When refreshing OAuth 2.0 tokens, this error happen for a few reasons including:
- There’s an outage on QuickBooks
- If the refresh token has expired or revoked
For additional details, check out this document.
Resolution
If you are getting an [.inline-code-highlight]invalid_grant[.inline-code-highlight] error when getting the access (bearer token):
- Make sure the redirect URI in your request matches the one provided in your app’s keys & credentials setting.
- Verify that the correct Client ID and Client Secret are used to create the base64 encoded authorization string.

If you are getting an [.inline-code-highlight]invalid_grant[.inline-code-highlight] error when refreshing tokens:
- Check if there’s an outage for QuickBooks Online API from the status page.
- Try requesting for a new pair of access and refresh tokens.
QuickBooks bearer token request
QuickBooks refresh token request
Hopefully this helps you solve the QuickBooks [.inline-code-highlight]invalid_grant[.inline-code-highlight] error.
Fully managed QuickBooks auth
If you want to avoid dealing with auth errors again while building a native QuickBooks (or any other) integration for your app, try out Paragon.
Access/refresh token management is handled by Paragon's authentication layer for any 3rd party SaaS integration you need to build, so you can focus on implementing your integration logic instead of fixing errors such as the QuickBooks [.inline-code-highlight]invalid_grant[.inline-code-highlight] error.
With a single [.inline-code-highlight]paragon.connect('salesforce');[.inline-code-highlight] call, the Paragon SDK will handle the entire authorization flow and refreshes tokens on behalf of your customers.

Learn more about Paragon's embedded integration platform for developers and sign up for a free trial here.