When I try to use my Google Market I get a message that says Authentication required. Please log into your Google Account. When I try to log into my Gmail account through the Gmail App is says I do not have a connection. When I go into my gmail account through the browser on my Android tablet I have not problems. I have been able to download items from the market until this weekend. When I try to sign in to the account as a new account it says that a my gmail account is already on this android device. I cannot find out how to log out and back in under settings. I cannot use my gmail account or the google market on my android tablet.