MacOS app renders blank screen with WKWebView

I'm not sure there are differences of WKWebView usage between iOS app and MacOS app. There I have an issue that a web view on the storyboard can not load a request. Typically there is always the white screen, implies nothing loads.

Finally, I found the solution here. In the Capabilities tab of the project target, it's App Sandbox, check the Network: Outgoing Connections (Client).

Screen Shot 2019-07-25 at 22.28.10.png