VPN Gateway: Upgrade from VpnGw1 to VpnGw1AZ — Deployment Validation Failure

Mathew K Varghese 0 Reputation points
2026-09-29T11:04:45.6533333+00:00

Problem description

I am trying to upgrade my Azure VPN Gateway from SKU VpnGw1 to VpnGw1AZ, but the deployment fails during validation. The only error captured is "Deployment validation failed". I need assistance understanding the specific cause of this validation failure and how to resolve it.

Environment

Azure VPN Gateway, current SKU: VpnGw1, intended SKU: VpnGw1AZ, public IP SKU: Standard, region: not specified.

What I've already tried

I attempted the upgrade through the Azure portal following the guidance provided for SKU migration. The upgrade fails at deployment validation with a generic error message. No additional troubleshooting steps, diagnostics, or follow-up actions have been documented.

Current status

Currently, the gateway remains on VpnGw1, and the validation failure prevents the SKU upgrade. I am seeking detailed error information and guidance on resolving the validation issues to complete the upgrade.

Azure VPN Gateway
Azure VPN Gateway

An Azure service that enables the connection of on-premises networks to Azure through site-to-site virtual private networks.

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  1. Mathew K Varghese 0 Reputation points
    2026-09-30T04:34:08.5966667+00:00

    The gateway is running in East US region.
    Gateway subnet - 10.0.6.32/27
    It is configured with one public IP with standard sku.

    Deployment validation failed

    Deployment validation failed. Additional details from the underlying API that might be helpful: The template deployment 'VirtualNetworkGatewayUpdate-20260930100119' is not valid according to the validation procedure. The following resource provider(s) - 'Microsoft.Network/virtualNetworkGateways (2026-01-01)' reported preflight validation errors. Tracking id is '29737332-a2b7-4889-86c3-6861869a9a01'. See inner errors for details.

    This is the error we are getting.

    Could you please help me to find the exact issue and resolve it.

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  2. Mathew K Varghese 0 Reputation points
    2026-09-30T04:32:39.1166667+00:00

    The gateway is running in East US region.
    Gateway subnet - 10.0.6.32/27
    It is configured with one public IP with standard sku.

    Deployment validation failed

    Deployment validation failed. Additional details from the underlying API that might be helpful: The template deployment 'VirtualNetworkGatewayUpdate-20260930100119' is not valid according to the validation procedure. The following resource provider(s) - 'Microsoft.Network/virtualNetworkGateways (2026-01-01)' reported preflight validation errors. Tracking id is '29737332-a2b7-4889-86c3-6861869a9a01'. See inner errors for details.

    This is the error we are getting.

    Could you please help me to find the exact issue and resolve it.

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  3. Jose Benjamin Solis Nolasco 12,691 Reputation points Volunteer Moderator
    2026-09-29T15:34:45.3033333+00:00

    Welcome to Microsoft Q&A

    Hello @Mathew K Varghese , Thank you for the details.

    A few common causes for VpnGw1 → VpnGw1AZ validation failures are:

    • The gateway is deployed in a region that does not support Availability Zone VPN Gateway SKUs.
    • The associated GatewaySubnet does not meet the minimum sizing requirements.
    • The Public IP configuration is not compatible with the target AZ SKU.
    • There is an existing gateway configuration or dependency that is not supported with zone-redundant gateways.

    Since the portal only shows "Deployment validation failed", I would recommend checking Portal → Resource Group → Deployments and opening the failed deployment operation. In many cases, the detailed validation error contains the exact resource and property causing the failure.

    References

    If my answer helped you resolve your issue, please consider marking it as the correct answer. This helps others in the community find solutions more easily.

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