WebView can't navigate to local sites using https

[PoulBak]

I'm submitting a...

Bug report (I searched for similar issues and did not find one)

Current behavior

I have some local web sites, that I can navigate to using 'http'. Now I have installed server certificates and I can browse to them in ALL browsers using 'https'. The certificates are trusted, this works fine. However, in WebView, I can only browse to the sites using 'http'. I have set 'IsPrivateNetworkClientServerCapabilityEnabled' to true. When I try using 'https' nothing happens, no page loaded, just white space.

(I can browse to external sites using 'https').

Expected behavior

Local https sites should be treated exactly the same as external sites when 'IsPrivateNetworkClientServerCapabilityEnabled' is true, allowing https access.

Minimal reproduction of the problem with instructions

You have to have a local site, where you have installed certificates, so they are browsable using https, using any browser. Then simply navigate to the site in WebView, using https.

Environment

Nuget Package(s): 

Package Version(s): v6.00 Preview 9.1

Windows 10 Build Number:
- [X] Windows 10 version 1903 with all updates
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] Insider Build (build number: )

App min and target version:
- [x ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] Insider Build (xxxxx)

Device form factor:
- [ x] Desktop
- [ ] Mobile
- [ ] Xbox
- [ ] Surface Hub
- [ ] IoT

Visual Studio 
- [X] 2019 version 16.3.4
- [ ] 2017 (version: )
- [ ] 2017 Preview (version: )

[Agent-JY]

I have a simular issue. Websites with a self signed certificate don't work