Q: "unable to sign in to apple tv at this time" error msg

Hello, Barbara. 

Thank you for visiting Apple support Communities. 

Here are some troubleshooting steps that I would recommend when experiencing this issue.  Start with the section labeled If you are unable to access or play content while connected to a Wi-Fi network.

Apple TV (2nd and 3rd generation): Troubleshooting Wi-Fi networks and connections

http://support.apple.com/kb/TS4546

Cheers,

Jason H.