Q: currently restore the ipod cannot because it could not establish a link

If the message said could not contact the update server then:

- Powering off and then back on your router.

- iTunes for Windows: iTunes cannot contact the iPhone, iPad, or iPod software update server

- Change the DNS to either Google's or Open DNS servers

Public DNS — Google Developers

OpenDNS IP Addresses

- Try on another computer/network

- Wait if it is an Apple problem

Otherwise I do not understand what the message said.

Did the message say the update server could not be contacted? If not what did it say?

Did you try when connect to another network?

All you can do is wait since it is likely an Apple problem.