Cannot RDP to Azure VM - Internal Error 0x4

Question

Cannot RDP to Azure VM - Internal Error 0x4

Brent Long 6

Starting this morning, I cannot RDP to my VM using the public IP.

My RDP allow list includes my IP address.
RDP troubleshooter shows no issues.
I can RDP to the machine from another VM in azure using the private IP address.
I tried changing (any) settings as suggested in a number of posts.
Reboot did not resolve the issue.
Tried updating VM system properties: Remote Desktop: Allow connections only from computers running Remote Desktop with Network Level Authentication - no difference whether checked or not.

RDC: Shell and control version 10.0.22621, Network Level Authentication supported, RDP 10.11 supported.

Error: Remote Desktop Connection, An internal error has occurred., Error code: 0x4, Extended error code: 0x0

Any suggestions?

kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2023-07-27T00:50:38.88+00:00

Hello, @Brent Long !

Are you still running into this RDP error?
Brent Long 6 Reputation points

2023-07-31T18:45:52.9033333+00:00

Yes. I cannot get to the machine other than going through a different one. And For some reason I can't open tickets anymore. I had one open for RDP connectivity a few months back, but it resolved itself. I've even upsized the machine, but still cannot RDP to it from external.
kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2023-08-01T06:47:06.92+00:00

Hello, @Brent Long !

The fact that RDP works successfully when using the private IP but not the public IP would have me look at your Network Security Group (which it sounds like you've done although there is sometimes a lot of ground to cover here). If that's not the cause, then I would look at your public IP. From the Detailed RDP troubleshooting documentation:

The public IP address of the VM or the cloud service containing the VM (also called the virtual IP address VIP) has changed. The RDP failure could be because your DNS client cache still has the old IP address registered for the DNS name. Flush your DNS client cache and try connecting the VM again. Or try connecting directly with the new VIP.

Also, if the VM was created using the Classic deployment model and can be reached via RDP by another VM:

The endpoint configuration for Remote Desktop traffic on the target VM: The private TCP port of the endpoint must match the TCP port on which the VM's Remote Desktop service is listening (default is 3389). The ACL for the Remote Desktop traffic endpoint on the target VM: ACLs allow you to specify allowed or denied incoming traffic from the Internet based on its source IP address. Misconfigured ACLs can prevent incoming Remote Desktop traffic to the endpoint. Check your ACLs to ensure that incoming traffic from your public IP addresses of your proxy or other edge server is allowed. For more information, see What is a Network Access Control List (ACL)?
kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2023-08-02T22:30:58.83+00:00

Hello, @Brent Long !

Just checking in to see how things are going. If this hasn't resolved your issue, please let us know in the comments so we can continue to troubleshoot this issue. If it has been helpful, let's document the solution for anyone else who may run into this.

1 answer

Your answer

kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2023-07-27T00:50:38.88+00:00

Hello, @Brent Long !

Are you still running into this RDP error?
Brent Long 6 Reputation points

2023-07-31T18:45:52.9033333+00:00

Yes. I cannot get to the machine other than going through a different one. And For some reason I can't open tickets anymore. I had one open for RDP connectivity a few months back, but it resolved itself. I've even upsized the machine, but still cannot RDP to it from external.
kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2023-08-01T06:47:06.92+00:00

Hello, @Brent Long !

The fact that RDP works successfully when using the private IP but not the public IP would have me look at your Network Security Group (which it sounds like you've done although there is sometimes a lot of ground to cover here). If that's not the cause, then I would look at your public IP. From the Detailed RDP troubleshooting documentation:

The public IP address of the VM or the cloud service containing the VM (also called the virtual IP address VIP) has changed. The RDP failure could be because your DNS client cache still has the old IP address registered for the DNS name. Flush your DNS client cache and try connecting the VM again. Or try connecting directly with the new VIP.

Also, if the VM was created using the Classic deployment model and can be reached via RDP by another VM:

The endpoint configuration for Remote Desktop traffic on the target VM: The private TCP port of the endpoint must match the TCP port on which the VM's Remote Desktop service is listening (default is 3389). The ACL for the Remote Desktop traffic endpoint on the target VM: ACLs allow you to specify allowed or denied incoming traffic from the Internet based on its source IP address. Misconfigured ACLs can prevent incoming Remote Desktop traffic to the endpoint. Check your ACLs to ensure that incoming traffic from your public IP addresses of your proxy or other edge server is allowed. For more information, see What is a Network Access Control List (ACL)?
kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2023-08-02T22:30:58.83+00:00

Hello, @Brent Long !

Just checking in to see how things are going. If this hasn't resolved your issue, please let us know in the comments so we can continue to troubleshoot this issue. If it has been helpful, let's document the solution for anyone else who may run into this.

Answer 1

Michael Durkan 12,241 MVP

Hi

Is there an NSG associated with the NIC of the VM or the Subnet that it sits on?

Check and make sure that no NSG rules have changed, you could also try disassociating the NSG from the NIC/Subnet to see if RDP works. If that works, try re-associating the NSG and try again - I've seen issues like this previously where this action can help.

Hope this helps,

Thanks

Michael Durkan

If the reply was helpful please upvote and/or accept as answer as this helps others in the community with similar questions. Thanks!

Brent Long 6 Reputation points

2023-07-12T18:43:13.4566667+00:00

@Michael Durkan Thanks for the response. There is an NSG, and no changes have been made. I disassociated it from the NSG to the NSG that's working for other VMs, but still got the same 0x4 error. The only way I can get to the machine is via another VM in my account. Any other suggestions?
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Cannot RDP to Azure VM - Internal Error 0x4

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