Marketo Access token expired

Marketo authentication for client_credentials expects the client_id and client_secret as query parameters. If you uncheck the last box, “Send Client Data as Basic Auth header” things should work properly (that should be used if the authentication documentation talks about sending “client details in the Authorization header”).

You’ll want to then click the “Authorize” button, then when you get updates, the “Apply” button. You’re also able to remove the auth endpoint config, client_credentials OAuth2 only makes a call out to the Token Endpoint. OAuth2 coming from client_credentials typically doesn’t have a refresh operation to make, it simply does a re-authorization during that process, you’ll notice that the Marketo documentation even shows that there’s no refresh_token returned in the response from the token endpoint. But our refresh operation will take care of re-authenticating for client_credentials or performing a refresh if a refresh_token is available, so you’ll want to keep the checkbox checked.

ResponseOfIdentity {
    access_token (string, optional): The token that you pass with subsequent calls to authenticate with the target instance,
    scope (string, optional): The owning API-only user of the custom service that was used to authenticate,
    expires_in (integer, optional): Remaining lifespan of the current token in seconds,
    token_type (string, optional): The OAuth authentication method = ['bearer']
}