See the picture. I am not able to download files to install the ghc etc, not sure if it is caused by the VPN. I am using it in China but I installed it successfully by using a VPN once before as well. Looking forward to your help.
Stack documentation has some information for Chinese users - https://docs.haskellstack.org/en/stable/install_and_upgrade/#china-based-users
I recently had similar (then same?) problem. I was able to fix it by upgrading stack. See https://stackoverflow.com/questions/57516944/stack-new-command-failing-to-download-build-plan-for-lts-14-1