>Strange. I would not assume Shanky write this solution while account doesn't exist. I don't know, I suggest to leave a comment directly to that article.
I finally found it. This NT Authority is quite confusing. We simply have to select the System account. This will place it as NT Authority\System. Trying to search for NT Authority would not find anything much. There is some naming convention that need to be adjusted here.
I will install with that account. I will see in about 10 minutes if this works.