OWRT SSTP client Keenetic server

Keenetic Giga works as an SSTP server. I can connect through my Android phone via SSTP, everything works. OpenWrt 23.05.2 on Asus RT-N 12 VP B1 installed SSTP (sstp-client luci-proto-sstp)

config interface 'VPN'
option proto 'sstp'
option server 'MyServer.keenetic.link'
option username 'MyName'
option password 'MyPass'
option log_level '0'

No connection. There are such entries in the log

Fri Mar 22 19:37:05 2024 local0.debug sstpc[3016]: Unrecoverable socket error, 1
Fri Mar 22 19:37:05 2024 local0.debug sstpc[3016]: HTTP handshake with server failed
Fri Mar 22 19:37:10 2024 daemon.notice netifd: VPN (3016): **Error: HTTP handshake with server failed, (-1)
Fri Mar 22 19:37:10 2024 daemon.notice netifd: VPN (2936): Command failed: ubus call network.interface notify_proto { "action": 0, "ifname": "sstp-VPN", "link-up": true, "keep": false, "interface": "VPN" } (Unknown error)

Please help me set it up

I’ll answer myself: it is necessary to add

option sstp_options '--tls-ext'