Ledong's server may be down (this is not the first time) ..................................................................................................................................................
If this martial arts error occurs, it may be that the 6th generation cpu is not compatible with secrom encryption. If yours is not a 6th generation cpu, don't consider it. If it is a 6th generation cpu, check the bios update. If there is no update, don't worry.
It turns out that connecting a CD-ROM drive to a computer can solve this problem (I don't know if a virtual CD-ROM drive can work without a CD-ROM drive). I'm not sure if this will work. ...