Unable to join a computer to domain

Question

We are trying to re join computers to domain but getting error message that duplicate host name already exist in domain. Until AD administrator removed the duplicate host entry unable to join the computer to domain

Answer 1

Sounds like the account used to join doesn't have enough permissions. Usually because the computer was joined previously by using different computer account credentials. (Assuming you did not join it to domain). So you must first delete the existing account or get full permissions on the account.
https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-2000-server/cc961817(v=technet.10)?redirectedfrom=MSDN

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Answer 2

Make sure the specific user or a specific group is provided with the permission to add or to remove computer objects to the domain on the organizational unit (OU) through the Delegation Wizard. Also read on here.
https://learn.microsoft.com/en-US/troubleshoot/windows-server/identity/access-denied-when-joining-computers

--please don't forget to upvote and Accept as answer if the reply is helpful--