This error can occur when the IP address has not been added to the White List.
To resolve, login to Luminate Online:
- Navigate to Setup > Site Options
- Select the Open API Configuration tab
- Click Edit Server API Configuration
- Under Add a new IP Range, enter the IP address
- Click Add New IP Range to list
- Click Save
- Click Finish
Note: The username and password is also found on this screen. Make sure these credentials match what is displayed in the Options screen within the Luminate Online Plugin within The Raiser's Edge.