I have error 21 while restoring the system. Do you have a solution?

Error 20, 21, 23, 26, 28, 29, 34, 36, 37, 40

These errors typically occur when security software interferes with the restore and update process. FollowTroubleshooting security software issues to resolve this issue. In rare cases, these errors may be a hardware issue. If the errors persist on another computer, the device may need service.

Some clues here:

itunes error 21