It’s not sure whether it’s the system or the M1 chip. The PC version client can’t log in. After the IOS / iPad version logs in, it can’t access the VPN intranet. After a long tour, I saw the open source third-party solution on GitHub, https://github.com/adrienverge/openfortivpn , run after installation

Sudo openfortivpn IP: Port — user name = user name — PPPD use peerdns = 1, which can be run.