Required Port 443 For Veeam Backup & Replication Is Occupied By Another Application ((new)) Site

Common culprits:

Developer tools or web servers left running from previous projects.

netstat -ano | findstr :443

: Run the following command: netstat -ano | findstr :443

To confirm exactly which application is holding the port, perform the following steps on the Veeam Backup Server:

Older desktop versions famously utilized port 443 as a fallback for incoming connections.