Lead Liaison does not presently support the Salesforce.com Sandbox environment. We are working on support for this, please stay tuned. 

The SFDC Sandbox environment uses the endpoint: test.salesforce.com

When switching from a SFDC Sandbox instance to your live SFDC instance Lead Liaison must intervene to reset a few configurations and disconnect your account from the Sandbox instance. Please contact your Revenue Performance Specialist when this service is needed.