Receiving Activation server error code when opening books in digital editions

I'm getting an error when I try to open ANY book in Adobe Digital Editions. I've opened all these books before & without a problem. The error states: "Activation server error code: E_AUTH_BAD_DEVICE_KEY_OR_PKCS12

I have uninstalled & reinstalled, but am getting the same error message. I bought a new Windows 10 PC last summer & am not sure if I have tried opening these books on this new PC until now. I may not have tried opening the books since I last opened them on the old Windows 7 PC. Is there something I need to do in order to get the books open on the new PC? My daughter can still open the same books on her laptop.