This API error indicates that the account you are using cannot access the data. This usually happens when there is a license problem or when the account owner removes your access (a typical agency problem).
Note: confirm that your add-in and all connectors are properly licensed (open the License wizard to confirm). In some scenarios, an expired connector license will result in random errors that include this one.
To fix the problem, confirm that the login account being used has access to the account being referenced in the query.
One other possibility is that you did not check box to authorize all the permissions requested during login. Open the connector’s Accounts wizard, select the account, and click the Refresh Login button to log in again. Make sure to select the checkboxes authorizing all requested permissions.