I hit an interesting problem today while trying to RDP to my Windows Azure VM using active directory credentials where I was getting an error message stating “An authentication error has occurred. The local security authority cannot be contacted.”.

SecurityAuthority

This VM was connected to a domain, my domain controller also being an Azure VM. At some point I must have set the DNS settings on my VM to obtain the DNS server address automatically rather than explicitly point at my domain controller and this was the cause of my problem. The problem didn’t present itself till I rebooted the VM in question, and since a bit of time had passed in between the two actions it wasn’t immediately obvious what the cause of the problem was.

To fix the issue I had to swap the credentials I was using to remote into my VM to a local account (when you provisioned the VM you would have created a local account, if you don’t remember these credentials or any other local account details that have RDP access then you might be in some trouble) which allowed me to successfully remote into the VM, and then had to set the DNS server address to explicitly point at the IP address of my domain controller. Props to Kevin P. Sullivan who mentioned this solution on this discussion board.

My colleague Mark Brimble has also pointed out to me that he has seen the exact same error for a newly provisioned local user on an on premise VM for which the password had to be reset upon the first login, so take note that there might be other causes for this error message.

For those of you who aren’t very familiar with network settings hopefully the below screenshots should guide you (the highlights denote what you need to click/change).

NetworkandSharing

Properties

TCPIP Properties

DNS Address

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