This post will step you through the troubleshooting steps for when you are unable to log into a Windows virtual machine (VM) in Azure via a remote desktop connection (aka RDP).
There are several things that can prevent you from successfully logging into a Windows VM in Azure. Some of these are human errors — configuration errors — some are regular faults that sometimes happen in a Windows installation, and some are things that can go wrong in the Azure fabric.
Note that many of the methods shown in this post change locations the Azure Portal faster than a whack-a-mole. The methods shared in this post are correct, but their locations will probably have changed since this post was written! You should be able to find the Azure Portal tools in the settings of the VM in question without much effort.
From time to time a VM might have a problem starting up or it might have crashed. If you have enabled Boot Diagnostics (under Diagnostics Settings), you can view a screenshot that is regularly taken of the VM’s “console” where you can see if your VM is running.
You can find this in Diagnose and Solve Problems (in the VM settings) > View Boot Diagnostics.
This option allows you to reach into the VM via a back door, the VM extension, to reset some configurations in the guest OS that can prevent successful remote desktop connections, such as enabling remote desktop in the Windows Firewall.
Go to the settings of the VM, browse to Diagnose and Solve Problems > Reset Password and select Reset Configuration Only as the mode before clicking Update.
Azure is secure by default. If you have done an advanced deployment of Azure VMs (i.e., you haven’t used a next-next-next method), then there is a chance that you either forgot to create a network security group (NSG) to allow RDP into the NIC or subnet of the VM. Check to see if there are any NSGs assigned, and if there are, double check the rules to make sure that RDP is being allowed in to your NIC or your subnet/network address.
I have experienced quite a few challenges with Azure load balancer administration in the Azure portal lately — I do not experience these issues when managing the load balancer via PowerShell or a JSON template. Every time I have a remote desktop issue, it’s been caused by a faulty NAT rule. Two things appear to happen:
Some VMs might not be placed behind a load balancer, such as the Basic A-Series machines, which are not supported by the load balancer. These machines require:
The VM relies on the Azure fabric to grant you access to it. If there is an underlying problem, then it might be reported in Resource Health, which you can find in the settings of the VM under Diagnose and Solve Problems. You can learn more about the health of the machine by clicking More Details.
If you are getting a username/password prompt to the VM, then you have network connectivity. Any problems now are probably down to failing memory, poor communications/documentation, or fat fingers — you need to reset the username and/or password, which is easily done via the VM Extension without any support calls to Microsoft.
You can find the Reset Password action in Diagnose and Solve Problems. Set the mode to Reset Password, enter the desired username and password, and click Update. A notification will appear to tell you when you can use these new credentials to sign in.
Let the jokes start — yes, restarting Windows can solve problems. There’s nothing like giving the jukebox a jolt to get it going again. Use the Restart action in the VM settings in the Azure Portal to trigger a restart.
If there is a localized issue in Azure, then you can move your VM to a different host. Doing so can often solve remote desktop issues that aren’t related to user configuration. You can trigger a redeploy action in Diagnose and Solve Problems.
Note that this action restarts the VM and you will lose anything stored on the temp drive.