Why am I getting invalid code and invalid redirect URI error?

Invalid code

Grant type	Reason
If the grant_type is authorization_code	You will get the invalid_code error when you try to reuse or use an expired code. The code value generated using /oauth/v2/auth is valid only for two minutes and is only one time usable.
If the grant_type is refresh_token	You will get an invalid_code error if the users have manually revoked their refresh token either during password reset or via Connected Apps, Devices sign-in. Refresh tokens don't expire unless you manually delete them.

Invalid_redirect_uri

The Redirect URI you pass in /oauth/v2/auth must exactly match with the one you have registered in the Zoho API console.

For example, if you provide the redirect URI as https://www.zylker.com in the API console and while generating the OAuth token if it is provided as https://www.zylker.com/callback, then you will face this error. Hence ensure that your providing the exact same redirect URI in both places.

For detailed information, please refer to our OAuth documentation