Sandbox Login Issue

This is from help documentation for Create a Sandbox:

When your sandbox is ready for use, you receive a notification email that your sandbox has completed copying. To access your sandbox, click the link in the notification email. Users can log in to the sandbox at https://test.salesforce.com by appending .sandbox_name to their Salesforce usernames. For example, if a username for a production org is user1@acme.com, and the sandbox is named test the modified username to log in to the sandbox is user1@acme.com.test. Salesforce automatically changes sandbox usernames, but not passwords. If you created the sandbox, then you should have received that email. If not, then check with the administrator who created the sandbox to reset your email in the new sandbox. User can login Salesforce sandbox through test.salesforce.com and by clicking login button. Login button is only displayed to system administrator. When Log in button is clicked, Salesforce.com will automatically redirects to Sandbox page. When we login Salesforce Sandbox we will find Sandbox name as shown above.