Build Cesium for Unreal from source problems

Cesium for Unreal
1 
I follow the instructions in “https://github.com/CesiumGS/cesium-unreal/blob/ue5-main/Documentation/developer-setup-windows.md”.
After I excute the ``git clone --recursive https://github.com/CesiumGS/cesium-unreal.git

``command,it stuck as the picture below shows:

360截图20230827220807098
360截图20230827220807098979×517 116 KB

And also show “fatal: unable to access ‘GitHub - nothings/stb: stb single-file public domain libraries for C/C++’: OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to github.com:443
fatal: clone of ‘GitHub - nothings/stb: stb single-file public domain libraries for C/C++’ into submodule path ‘E:/Dev/cesium-unreal-samples/Plugins/cesium-unreal/extern/cesium-native/extern/stb’ failed”
I have spend three days,and try many times,and try many solution in the internet,all not work.
I also tried to download the packages manully,and build,it produces many errors
Would somebody tell me why?
My system is Win10,I use VPN

2

It seems like there is something wrong either with your SSH client or with your network. I’d suggest uninstalling and reinstall Git for Windows, and let it use its bundled SSH when you install it.