Unexplained failure

Thank you.

From the online installer log files I couldn't quite determine if the installation process had gotten as far as attempting to install Flash Player itself (online installer downloads and installs Flash Player silently in the background), but the failure is prior to this point as the FlashInstall.log file doesn't have anything recent in it.  I do see an error in the online installer log file referring to a proxy server, which you indicate you don't use.  It could be a false error or something in how your system is configured to access the internet is causing it to thing it's using a proxy.

To see how how Firefox is accessing the internet launch Firefox and navigate to about:preferences#advanced and then click on the Settings button in the Connection section.  A new window will pop-up. This will display if it's configured to use a proxy or not.

Windows 10 has a Proxy config listed in both Settings and in the Control Panel:

• Settings > Netowrk & Internet > Proxy and see if it's configured there
• Control Panel > Internet Options > Connections > LAN Settings

Ensure all of these are not configured to use a proxy

I'm going to forward the installer log files to the online installer team to troubleshoot further.  They may have more questions for you after they review it.  In the mean time, you can try using the offline installer posted at the bottom of the Installation problems | Flash Player | Windows 7 and earlier in the 'Still having problems' section.  This is the full installer and doesn't download anything silently in the background.