How to fix Error 7850 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 7850 — HTTP Namespace Registration Failure

Why This Error Happens

This error occurs because the SQL Server Service account lacks the necessary permissions within the Windows HTTP.sys kernel driver to bind to the specified URL endpoint (commonly used for SOAP/HTTP endpoints or Service Broker). Windows Server 2025 and Windows 11 enforce strict URL ACL reservations, meaning that unless an explicit namespace reservation exists for that specific account (via netsh http add urlacl or sp_reserve_http_namespace), the registration will be rejected. This is frequently triggered after a service account change, a server migration, or a fresh installation where the HTTP namespace was never initialized.

Step-by-Step Resolution Guide

Step 1: Verify the Current Service Account

  • Open SQL Server Configuration Manager.
  • Navigate to SQL Server Services and check the Log On As account for the SQL Server instance.
  • Note the exact domain\username or virtual account (e.g., NT SERVICE\MSSQLSERVER) currently in use.

Step 2: Reserve the URL Namespace via T-SQL

  • Open a new query window in SQL Server Management Studio (SSMS) with administrative privileges.
  • Execute the system stored procedure to manually reserve the namespace for the account:
  EXEC sp_reserve_http_namespace N'http://YourServerName:80/sql/endpoint'
  • Ensure the URL matches exactly (including port and case-sensitivity) the one referenced in the Error 7850 log entry.

Step 3: Validate or Add the URL ACL via Netsh (Alternative Method)

  • If the stored procedure fails due to driver-level locks, open an elevated Command Prompt (Run as Administrator).
  • Check existing reservations:
  netsh http show urlacl
  • If the URL is missing, add it manually, substituting your specific service account:
  netsh http add urlacl url=http://+:80/sql/endpoint user=DOMAIN\SQLServiceAccount

Step 4: Restart the SQL Server Service

  • Return to SQL Server Configuration Manager.
  • Right-click the SQL Server instance and select Restart to force the Database Engine to re-read the HTTP.sys reservations.
  • Monitor the SQL Server Error Log to confirm Error 7850 does not reappear during the startup sequence.

Alternative or Verification Steps

  • Verification: Re-run netsh http show urlacl in an elevated terminal and confirm the specific URL and User SID now appear in the output list with “Listen” set to Yes.
  • Alternative: If permissions issues persist due to Group Policy restrictions on Windows Server 2025, grant the service account local Administrator rights temporarily to isolate whether the issue is HTTP.sys-specific or a broader OS-level Group Policy block.