In Local Management shell gives error 'Invoke-WebRequest : The remote server returned an error: (401) Unauthorized'

HI 

I download the SharePoint Online management shell in my desktop and try to connect the Office 365 site.

But i am unable to connect to the site. Please let me know why i am not connect to online site.

Tried Script :

 $username ="your domain/username"
        $password =ConvertTo-SecureString"your password"-AsPlainText-Force
        $cred =new-object-typenameSystem.Management.Automation.PSCredential-argumentlist $username, $passwordInvoke-WebRequest-Credential $cred -Uri http://spurl