PiktTv on my AppleTV runs as smooh as butter. Using the latest release and using a wifi connection. Have you done an uninstall, restart the Apple TV then install the app?
Are you using a hard wired or wireless connection.
I think this is related to a bug with Apple's Zero Sign On. The workaround right now, if prompted for your TV provider during the reset/install process, select ‘Do not allow’.
If your Apple TV is already set up and you're having trouble with the Pik TV app, go to the Apple TV Home Screen, then navigate to Settings -> Users and Accounts -> Apple TV Accounts -> TV Provider -> Sign Out