I am trying to add an second domain controller (DC) to my domain. The server is running Windows Server 2012 R2. After getting the error when promoting it to an domain controller I tried uninstalling the AD DS role and joining the domain as you would do with an regular computer/server. I got the same error there to.

The error I get is: "The following error occurred attempting to join the domain "example.com". The user name or password is incorrect.".

I did join one other server to the domain with the same user and the same password and I am sure that I type the correct password. I've also tried to copy the password from Notepad into the password field. I am able to sign in to the other DC with the same username and password. The account that I am using is the built in Administrator account.

My question is how I should fix the error saying that I use the wrong user name or password.

  • What are you trying to do exactly? To build are forest maybe? Or do a LB setup? You might want to look at this if it is a forest you want.
    – MrMajestyk
    Feb 26 '15 at 10:26
  • Try qualifying the Domain Admin's credentials during the join. e.g. instead of parentdomain\Administrator try parentdomain.example.com\Administrator or the UPN Administrator@parentdomain.example.com.
    – jscott
    Feb 26 '15 at 11:02
  • @jscott I will try that later. I did by mistake crash my DC1 so I need to restart it physicaly.That can't be done until next week.
    – Dempa
    Mar 1 '15 at 12:13

The account that I am using is the built in Administrator account.

You have to use an account which is part of the Domain Admin group to join a client to your domain. Also make sure the DNS settings on the client are correct.

  • The account is in the Domain Admins group and the DNS settings is pointing at the first DC.
    – Dempa
    Feb 26 '15 at 10:17
  • Anything in the Event Logs from your client and DC? First DC is also your DNS server?
    – duenni
    Feb 26 '15 at 10:26

Make sure you have joined the server to the domain as a domain member and rebooted before trying to promote it to a Domain Controller.


Also, try on the machine itself when you try to join it rather than RDP.


I know this question is very old, but it's one of the first Google results for this problem.

For me the issue was both my domain controllers had a second, conflicting IP address. Once I removed these from the network adapter I could successfully join the second machine to the domain.

  • This does not really answer the question. If you have a different question, you can ask it by clicking Ask Question. To get notified when this question gets new answers, you can follow this question. Once you have enough reputation, you can also add a bounty to draw more attention to this question. - From Review
    – djdomi
    Nov 4 at 19:35
  • How does it not answer the question? I had exactly this issue - an incorrect username/password error when attempting to join a second domain controller to an existing one - and the issue was because the network adapters on both machines had a second, duplicate IP address associated with them (probably a result of the VM template they were built off). Was the issue I didn't give enough detail in my answer, because the answer is certainly correct?
    – Brandon H
    Nov 5 at 20:17

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