I can't find any information on what the process is to get this notice removed. Your site was clearly visible blocked by Windows Defender SmartScreen. Your problem is addressed in the Windows Defender SmartScreen FAQ or your might just have looked further into the More Information part of the message. To cite from the FAQ: Q.

Aug 20, 2012 · In the Action Center window, click on the Change Windows SmartScreen settings shown in the left side menu. This would open the Windows SmartScreen options window. In this window, choose the option Don’t do anything (turn off Windows SmartScreen) as shown in the picture below: Click the OK button to save the changes. That’s it. Apr 09, 2015 · Now select the Action Center option, or click on Security and Maintenance in Windows 10. In the left pane, click on the Change SmartScreen settings link. Now SmartScreen Settings window will appear. You will see three options there. Check the last option “Don’t do anything (Turn Off Windows SmartScreen)” and press OK. to disable SmartScreen. Mar 08, 2010 · You have two options to configure SmartScreen. First, in the Advanced options. Go to Advanced and scroll down until you find "Enable Windows Defender SmartScreen". Uncheck the option and click on ok to turn it off completely. Zones. The second option gives you more control over the feature as you can turn it on or off for individual zones. Mar 21, 2019 · Select “Windows Defender settings” from the results. On the right pane, under “Windows Security”, go to “App & browser control”. Under the “Check apps and files” section, you’ll notice that Windows Defender SmartScreen is, by default, set to “Warn”. Click the “Off” button to disable it. The Windows SmartScreen alert will go away after enough people download and run it. If your software is not that popular then the warning will never go away and there is not much you can do about it. You can try to get yourself whitelisted but I would not hold my breath while waiting for that.

Many people do not wish to get ever-increasing notifications from the software they use for the protection of their computer. If they use the Windows Defender Antivirus, then they can disable the notifications from it through the virus and threat protection settings. They get 100% satisfaction from a very welcome silent detection mode.

May 19, 2020 Disable Smart Screen for Edge downloads in Windows 10 Jul 21, 2016 Turn off "Windows protected your PC" (Windows SmartScreen

How to fix Windows SmartScreen can't be reached right now

Jun 09, 2020 · Windows SmartScreen is kept in its place to protect users from installing malicious software. Additionally, Microsoft has also improved the SmartScreen filter in Windows 10 that will be integrated with IE and Microsoft Edge that will keep you protected from malicious websites. You will be glad that Windows protected your PC with the SmartScreen.