XMLHttpRequest: Network Error 0x2efd, Could not complete the operation due to error 00002efd.
This is quite a low-level error from WinHTTP, actually this is the generic error for network connectivity issues: ERROR_INTERNET_CANNOT_CONNECT (12029).
The application is using the Bing Maps SDK, so it definitely tries to connect to the network, therefore the Internet (Client) capability was checked in the package.appxmanifest file. Other Bing Maps apps were working properly, so the issue was probably not on server side.
After some experimenting I found, that the app works, if I enable the Private Networks (Client & Server) capability as well. It’s quite strange, because the privateNetworkClientServer capability means, that according to the docs “A home or work network – the app can send information to or from your computer and other computers on the same network.”, but it was not the case.
This morning I restarted the computer, and now the app works perfectly with only the internetClient capability. Strange.