I cannot access :8123 (:4357 is fine). When I do a windows diagnostic, it says it can ping 8123 but it is being denied access and shows a little yellow warning triangle? Anyone run into this. It happened all of a sudden and now I have no access. Do you think a rebuild with backup will solve this? Weird.
Have you done the allow exception in the browser security for the address:8123?
That is only required if using https and the ip address.
Scott, what is the full URL you are trying to access?
Look at the monitor on the HA installation and see if it is ready and have listed an IP address for 8123
You cannot ping a port, only tcp addresses 
If you want to check a port, use telnet command 
https://192.168.1.72:8123
and this happened OUT OF NOWHERE!!! Everything has been running perfectly for quite a while. No changes on my part.
Yes that will require a browser security exception.
Try clearing your browser cache or using a private/incognito tab.
Accept the risks if you get a security warning.
No luck with incognito tab. Also, note that NABU CASA is not receiving either. I have to believe it’s something with the NUC that HA is installed on. I haven’t changed any of the Windows permissions (although the firewall is turned off).
baffled!
even running Chrome on the NUC itself, its saying HomeAssistant is refusing to connect when trying :8123. HOWEVER, when trying :4357, its showing connected and healthy.
What does not the monitor day on the HA installation?
sorry WallyR…don’t understand the question.
This might be some new information for you. My Alexa is working fine triggering my home assistant devices. I’ve noticed that if the HA computer has crashed or powered off, Alexa does NOT work. So I know the HA computer is working and Alexa is communicating with it. I just cannot connect via NABU CASA or :8123 web browser.
The HA installation has a monitor output too, where messages might be posted.
If you run on a raspi, then connect a monitor to that. If it is a VM, then look at the VMs monitor.
I guess that’s the point. I installed 6 months ago with no issues…now it’s acting up and I cannot figure out why port 8123 is being blocked by the HA software or the VM. BTW, using VM VirtualBox.
would I check that from the VM computer or a Mac on the network?
Don’t use any of that. You should check does something like home assistant is listening to port 8123 for connections. How can you do it on superior oses I really don’t know.
the Linux I’m running for VM only will respond to “net stat”…I’m getting a ton of responses from the VM computer (192.168.1.72), but they are 5 digit port numbers starting at 49772.
Works perfectly well, and actually recommended
Yes that are “response ports”, random “free” ports in the upper segments of ports