Azure Bastion fails to connect over RDP - Black Screen

Question

I'm hoping somebody can help. I have tried to setup Bastion in my subscription and am hitting the following error on any VM I try to connect to. When I try to connect it opens a new browser window with black screen and to in the lower right corner I get a dialogue box saying...

'The network connection to the Bastion Host appears unstable.'

Then a dialogue box saying...

'The connection has been closed because the target machine is taking too long to respond. This is usually caused by network problems, such as a spotty wireless signal, or slow network speeds. Please check your network connection and try again or contact your system administrator.'

Bastion appears to be setup correctly, has its own dedicated /27 subnet within the same vnet as the VM's I'm trying to connect to. There is no NSG applied on either the VM or on the Bastion subnet. Presumably if no NSG is applied there should be nothing internally within Azure blocking it. Yet I cannot seem to establish a connection to any of my VM's.

Worth a mention I tried looking this up before posting and seen some people mentioning they had set their RDP port to something other than 3389, and resetting this back fixed the issue. I have not changed the RDP port on any VM and confirmed all are still set to 3389.

Any help would be appreciated.

Answer 1

Any other suggestions folks?

I'd really like to get Bastion working.

Answer 2

Just to add, I have created a new Bastion host in a separate vnet, also created the required dedicated subnet for Bastion. I then created a test VM and Bastion works perfectly within this vnet.

This seems to isolate the problem within my other vnet. Keeping in mind there is no NSG applied to the Bastion subnet or VM nic. What else in the vnet config would cause this? Is there any particular routing requirements? Anything in the Route Table I should look out for?

Answer 3

Azure Bastion is managed service, the troubleshooting for this one is hard.

The troubleshooting document is not good enought (https://learn.microsoft.com/en-gb/azure/bastion/troubleshoot?WT.mc_id=Portal-Microsoft_Azure_Health)

my case is,

I deleted the Azure Bastion service at weekend, and created it this morning, then I can't connect to my Windows VM.

The Bastion service is at "available" status, but I can't connect with error 'The network connection to the Bastion Host appears unstable.'

Finally i fixed it by stop and start the Windows VM.