but my question was not how to see on which port PRTG Web Server is running.
I appreciate your answer(btw. you need the extra "-a" parameter to see all listening ports)
but in my case I have clearly defined in the PRTG Administration Tool that I want to use 443(not 8443) and still from time to time it seems that the PRTG WebServer needs, for some reason, to use the other port.
What I already said before is that I have checked 443 and 8443 and I don't have any other process or WebServer running(overlapping) or using those ports.
The only thing/reason that I can think of would be that my windoze nuc is booting, thanks to the nvme disk, way too fast and the static ip(ip stack) is not fully initialized before the PRTG WebServer tries to start. But then again this never happened on other machines and also is not consistent with every reboot.
I will try a delay start and see if it helps.
Regards Florin Sfetea