The base URL of the Bullhorn CRM REST API.
This is used as the base URL of the Bullhorn CRM REST API. This is retrieved automatically during the OAuth flow in WEB mode. If you execute the OAuth flow manually in APP mode, you must specify this in the connection string, after getting it as an output of the GetOAuthAccessToken. Otherwise if InitiateOAuth is set to GETANDREFRESH, this value will be retrieved and saved for you under the hood.