When building using il2cpp for the windows platform HttpClient no longer works, you get an ConnectFailure exception.
I’ve submitted a simple reproduction case 1209901. I’m installing 2019.3.0f4 now to see if that fixes the issue. The issue does not show up in the editor or if you use mono instead of il2cpp, it affects both the Windows Desktop and UWP platforms. The MacOS and iOS platforms seem to work fine with il2cpp and HttpClient.
I also tested this in 2019.3.0f4 and it is broken there as well. It’s also broken in 2019.2.17f1, but works in 2019.2.13f1
Discovered something odd, on a different machine 2019.3 was able to build the il2cpp Windows version and HttpClient worked fine. The main difference that I can see is that the machine that it works on is older and has more dev things installed on it (multiple versions of VS, windows sdks etc), the one that it isn’t working on a new machine with just VS 2019.
So possibly il2cpp needs something on the machine to be there that isn’t on this particular machine?
I believe I tracked down the culprit to this, the machine that wasn’t working had the Windows 10 Preview SDK 10.0.19025.0 installed, and also the the 10.0.18362.0 SDK installed, I uninstalled the 19025 one and il2cpp started having issues compiling at all (couldn’t find assert.h) and then I decided to uninstall/reinstall 18362 and restart, and now it seems to be able to build without issue and the HttpClient works again. So my guess is that something in the 19025 SDK seems to be causing the issue.