The customer has a few options:
1. Fix their internet so they can connect to the activation servers: https://wyday.com/limelm/help/faq/#internet-error
2. If they can't or don't want to fix their internet access, then they can always re-activate offline: https://wyday.com/limelm/help/offline-activation/
3. They can also deactivate offline. But that's not necessary to solve their problem.