Last week I rebooted one of the management servers I use, everything looked fine, but the Veeam backup didn’t run that evening.
Veeam reported the following error:
“Task failed Error: No connection could be made because the traget actively refused it. ipaddress:443″
The issue in my case was that a recently installed application decided to use port 443 without asking, and started be fore VMware VirtualCenter server had a chance to start.
The solution was to stop the app, start VirtualCenter, then restart the application and configure it not to use port 443!