Before completing "Step 2: Alyce Authorization" in the Salesforce installation process, update your Alyce endpoint to reflect a sandbox installation. This should be done for all users involved in sandbox testing.
Navigate to Setup
Search for “Custom Settings“
Click the “Manage“ Action next to the “Alyce Endpoints“ Label.
Click "Edit" next to the Setup Owner.
Update the “AlyceBase“ field to a value of “ https://sandbox.alyce.com“.
NOTE: The default organization level value may indicate 'sandbox,' but that doesn't necessarily mean that all users involved in sandbox testing are properly set to the sandbox base URL. Please edit each user individually to confirm the proper setting.