[unable to shop from Marketplace get error Access to cashier.secondlife.com was denied]

if someone in the same household as you, used the same computer, and has not loved off their dashboard. and when you go to the marketplace to buy something, and cannot buy something, because it tells you. access to cashier.secondlife.com was deny 
you don't have authorization to view this page. 
HTTP error 403 
reload
when logging off other person dashboard then you are able to go and buy anything you want