Authenticates a Contact using a username and password, and returns its unique identifier on success.
| Method | /sites/{company-id}/ws/soap_v1.svc/AuthenticateContact | 
The request body is of type AuthenticateContact.
| Name | Description | Data Type | 
|---|---|---|
| userName | xml:string | |
| password | xml:string | 
|  | 
The response body is of type AuthenticateContactResponse.
| Name | Description | Data Type | 
|---|---|---|
| AuthenticateContactResult | guid | 
|  | 
 |