unable to add vendor pc to cs domain

Hello Team,

Previously we were able to add our new standardized Computer name into here on ARS, then we would be able to rename the vendor pc to the New name created in ARS then add the pc to the CS domain.

This would work without issue up until recently now we are getting an error saying "an account with the same name exists in active directory. re-using the account was blocked by security policy" We re-attempted with new names, and this has now happened on different occasions across SCAL. We are unable to put the new equipment into service.

Any ideas?