& Replication Is Occupied By Another Application !!hot!!: Required Port 443 For Veeam Backup

Lena groaned. AcmeCorp Unified Agent. The Swiss Army knife of cybersecurity that had been forced onto every server in the fleet three months ago. It intercepted all HTTPS traffic for deep packet inspection, certificate re-signing, and behavioral analysis. And it had planted its flag firmly on port 443.

Port 443 conflicts are common but easy to fix once you know what’s listening. In most cases, it’s a harmless local service like IIS or a chat app. By identifying the PID and stopping or reconfiguring the offender, you’ll get Veeam Backup & Replication installed without a hitch.

[Info] HTTPS listener started on 172.18.0.10:443. Ready to serve. Lena groaned

This creates a "Non-Standard" Veeam deployment. You must document this change thoroughly for future troubleshooting.

Go to the tab and sort by the PID column to find the matching application. It intercepted all HTTPS traffic for deep packet

If your Veeam Backup server doubles as a Hyper-V host, the native Hyper-V Replication engine might be configured to use HTTPS traffic over port 443. Open the Hyper-V Manager . Click Hyper-V Settings > Replication Configuration .

Before you can fix the issue, you must find out exactly which process is currently listening on port 443. Using Command Prompt (Netstat) In most cases, it’s a harmless local service

Still, if necessary: