After installing Unreal engine installer, I try to sign and says " can not Authenicate"

Hey megazord,

Have you tried uninstalling Launcher on your second system, redownloading it and reinstalling it? If you still have same issue after reinstalling Launcher, let us take a look at your Launcher log and we’ll see what we can do. Your log file will be located here: c:\users\YOUR_USER\appdata\local\unrealenginelauncher\saved\logs

Thanks!