Replication Is Occupied By Another Application Link - Required Port 443 For Veeam Backup

Title

Required port 443 for Veeam Backup & Replication is occupied by another application — how to identify and resolve

A Quick Word on Best Practices

• Avoid port conflicts from the start: Don’t install Veeam on a machine already running a web server, Skype, or SQL Server with Reporting Services.
• Use dedicated servers for Veeam backup components.
• Document your ports – Especially if you’re running multiple data protection tools in a lab or production environment.

Step 2: Is the Owner "System" (PID 4)? The HTTP.SYS Scenario

If the process is System (PID 4), the port is being reserved by the HTTP Kernel Driver (HTTP.SYS). You cannot kill PID 4. Instead, you must remove the URL reservation.

Run this command in an elevated CMD or PowerShell: Title Required port 443 for Veeam Backup &

netsh http show urlacl | findstr :443

This will list all URL reservations. Look for something like:
http://+:443/ or https://+:443/ reserved for a specific user or service group (e.g., NT SERVICE\SSRS).

To delete the reservation:

netsh http delete urlacl url=http://+:443/
netsh http delete urlacl url=https://+:443/

After deletion, restart the Veeam services or the installer.

Step 4: Restart & Retry

After freeing port 443:

• Restart the Veeam Backup Service (or reboot if unsure).
• Rerun the Veeam installation or configuration wizard.

Changing Veeam’s Port After Installation

If Veeam is already installed (but services fail to start due to port conflict):

1. Open Registry Editor (as admin).
2. Navigate to:
   HKLM\SOFTWARE\Veeam\Veeam Backup and Replication\
3. Modify the HttpPort DWORD to your new value (e.g., 8443).
4. Navigate to:
   HKLM\SOFTWARE\Veeam\Veeam Backup and Replication\VeeamRestAPI
5. Change the Port value to match.
6. Reboot the server.

3.3 Check for IIS Specifically

sc query W3SVC

If running, you will see STATE : RUNNING. Avoid port conflicts from the start: Don’t install

Step 4: SQL Server Reporting Services (SSRS)

SSRS is a notorious port 443 hog. Even if you stop the service, the URL reservation persists.

1. Open Reporting Services Configuration Manager.
2. Click Web Service URL and Web Portal URL.
3. Change the TCP Port from 443 to 4443.
4. Click Apply.
5. Run netsh http delete urlacl ... as shown in Step 2 to remove residual SSL reservations.
6. Restart SQL Server Reporting Services service.

Summary

Port 443 (HTTPS) is required by Veeam Backup & Replication for certain components and communication. If another application is already using port 443, replication, console connectivity or web components can fail. This post explains how to identify the conflicting process, safely free or change the port, and validate the fix. Step 2: Is the Owner "System" (PID 4)