CORP ADF Linked Service On-prem SQL Connection started failing from 7/19/2026

Question

Hello Team,

Existing CORP ADF Linked Service on-prem SQL connections are failing. Due this our team is unable to function. Please help at the earliest.

Answer 1

Hi,

From the screenshot, this is a SQL Server linked service using Windows authentication through a self-hosted integration runtime named WACAPPRODSQL2.

So the first thing to check is the self-hosted IR machine, because ADF is not connecting to the SQL Server directly from the cloud. The connection is made from the IR host.

Please check these items:

1. On the self-hosted IR machine, test SQL connectivity to:

WACAPPRODSQL2.redmond.corp.microsoft.com
Database: WACAPMD
User: REDMOND\gctquota

1. Confirm the domain account REDMOND\gctquota is not locked, expired, disabled, or using an old password.
2. Since the password is coming from Key Vault, confirm the latest Key Vault secret value is correct and that the linked service is reading the expected secret/version.
3. Restart the self-hosted IR service and confirm the IR is online and healthy in:

ADF > Manage > Integration runtimes

1. Run the self-hosted IR diagnostic tool from the IR machine to test connectivity to the SQL Server.
2. If this started recently, also check whether the IR version, SQL Server TLS/encryption settings, or linked service connector version changed. As a quick test, you can create a temporary linked service with minimal settings to isolate whether the issue is credentials, IR, or SQL Server connectivity.

The error message mentions firewall, but for an on-prem/corp SQL Server this usually means the IR machine must be able to reach the SQL Server over the network. It is not necessarily an Azure SQL firewall issue.

Also, please avoid posting tenant ID/subscription ID publicly. Share those only through a Microsoft support case or internal support channel.