Current date 2023-1-15 test, The script used is: https://github.com/hwdsl2/setup-ipsec-vpn
Test system Debian GNU/Linux 11 (bullseye) GCP virtual computer hardware configuration: E2-small Ports are all open! HTTP/HTTPS/IP Forwarding: Checked I'm not sure what is causing the problem,619 or 800 error. The free L2TP account I found online can be used normally, which proves that there is no problem with my computer settings. In the author's script, it is mentioned that the windows7 system needs to update the registry and restart. I did the same, but I still can't connect.