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Azure Bastion unavailable – cannot connect to VM (Unplanned Resource Health event, East US)

Bob Olsinski 0 Reputation points
2025-12-30T13:50:19.3333333+00:00

Details

We are unable to connect to a Windows VM using Azure Bastion. This was working previously and stopped suddenly today.

Environment

Azure Bastion (Standard)

Region: East US

Windows VM: AutomationRunner

Access method: Azure Portal → VM → Connect → Bastion (RDP)

NSG allows TCP 3389

VM is running and reachable inside the VNet

Symptoms

Bastion connection fails with:

“The network connection to the Bastion Host appears unstable”

“The Bastion Host has closed the connection”

Native RDP also fails
Password reset completed successfully
VM restarted multiple times

What we’ve already tried

  • Restarted VM
  • Deleted and recreated Bastion
  • Deleted VM (kept disk) and recreated VM
  • Verified NSG rules
  • Verified subnet (AzureBastionSubnet)
  • Tested from multiple browsers and machines

Azure Resource Health

Bastion shows Unplanned Outage

Message states Azure is working to automatically recover the Bastion host

Issue persists even after redeployment

Question Is there a known Bastion service issue in East US that would cause persistent connection failures even after redeployment? Is there any backend action Microsoft needs to take to restore this Bastion resource or migrate it to healthy infrastructure?

This appears to be a service-side Bastion failure, not a configuration issue.

Azure Bastion
Azure Bastion

An Azure service that provides private and fully managed Remote Desktop Protocol (RDP) and Secure Shell (SSH) access to virtual machines.

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  1. Venkatesan S 6,435 Reputation points Microsoft External Staff Moderator
    2025-12-30T14:12:10.3566667+00:00

    Hi Bob Olsinski,

    Welcome to Microsoft Q&A forum.

    As discussed in our Teams, your new VM creation worked perfectly.

    The Azure Bastion connection failure to your AutomationRunner VM ("network connection unstable" / "Bastion Host closed connection") was caused by an unplanned Resource Health event in East US around Dec 30, 2025.

    • Run Connection Troubleshoot from Bastion resource blade: Source=Bastion, Destination=VM private IP (TCP 3389).​
    • Verify AzureBastionSubnet NSG: Inbound 443 (AzureBastion tag), RDP 3389 from BastionSubnet to VM subnet.​
    • Check VM boot diagnostics/serial console: Confirm RDP listener active; temporarily disable Windows Firewall.

    Resolution Path

    • Monitor Resource Health in Bastion blade—event auto-resolved for most.​
    • Take VM snapshot (Disks > Create snapshot), create managed disk from it, attach as OS disk to new VM (same VNet/subnet).​
    • Or deploy fresh VM → Copy data via AzCopy from affected VM storage or Azure Backup restore.​​

    Reference:

    Kindly let us know if the above helps or you need further assistance on this issue.

    Please do not forget to 210246-screenshot-2021-12-10-121802.pngand “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

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