If your computer does not have internet access, ESET’s online activation with a License Key will fail. You need a Username/Password to activate manually.
Treat them like your License Key. Do not share publicly. If needed for an admin console, use secure channels. Eset Convert License Key To Username And Password
Return to license.eset.com – your Username/Password will still be there as long as the license is in your account. If not, contact support. If your computer does not have internet access,