I recently purchased an Intel NUC7i5BNH kit Mini-PC. I added 16 GB DDR4 RAM and a 1TB SATA disk drive. I installed Windows 10 Home Edition 64-bit.
The AC-8265 WiFi interface works fine in Hotspot mode. However, I can't get it to associate with my home's Access Point in infrastructure mode. The error message as seen in Windows Event Viewer is that the association failed for an unknown reason. The access point is a Linksys WRV200, offering 802.11g only, on 2.4GHz Channel 6. Security is WPA2-Personal. I have a number of other devices that connect to the AP just fine, so it is working correctly.
I've tried various versions of the device driver, and all of them exhibit the same behavior. I tried uninstalling the device and drivers and starting over. Right now, it's using driver version 18.104.22.168, which Windows "found" for me. I had also tried with a more recent driver version from the Intel drivers download page.
One odd thing is that Windows Device Manager reports a different driver version than do either Windows Network Troubleshooting or Windows Event Viewer system logs.
I'm really out of ideas. I received no useful advice in the Microsoft Windows 10 support community. They (somewhat arrogantly) told me to ask in the Intel support community.
I found the answer to my problem, by continued searching for web postings related to failed WiFi associations. I'm a bit embarrassed to admit...
The problem was that I'd enabled MAC address based connection limitation on my WiFi Access Point. I did that back when the 802.11i key-reuse security bug was originally announced. I forgot that I had done so. Ooops.
So, it seems that MAC based association rejection comes back as an "unknown reason".
That can happen to the best of us, specially with features that are often set up once, then never touched again. We're glad to hear you were able to figure out the source of the issue.
Please don't hesitate to contact us again if there's anything else we can help you with.