I finded out that Ubuntu since version 17 has a bug related to network-manager-sstp-gnome. It is possible to create SSTP configuration by selecting it from the popup network-manager menu. You can also input all correct credential data, but when you select this connection inattempting to connect, it happens nothing. In this case, you should use the nmcli console utility for Ubuntu's NetworkManager.
Dive a little bit to the world of command line magic:
sudo apt-get update &&
sudo apt-get upgrade &&
sudo add-apt-repository -y ppa:eivnaes/network-manager-sstp &&
sudo apt-get update && sudo apt-get install -y network-manager &&
sudo apt-get install -y sstp-client&&
sudo apt-get install -y network-manager-sstp &&
sudo apt-get install -y network-manager-sstp-gnome &&
sudo apt-get update
Now everything up-to-date on your PC so, you just need to run next piece of code from the sudo:
nmcli connection add \
save yes \
type vpn \
connection.interface-name ``name_in_ifconfig`` \
connection.id ``name_of_the_vpn_connection`` \
vpn.data gateway=``vpn_server_host_or_ip``,ignore-cert-warn=yes,lcp-echo-failure=5,lcp-echo-interval=30,nobsdcomp=yes,nodeflate=yes,password-flags=0,proxy-password-flags=0,refuse-chap=yes,refuse-eap=yes,refuse-pap=yes,user=``username`` \
vpn.secrets password=``password`` \
vpn.service-type org.freedesktop.NetworkManager.sstp
you just need to replace
with your own data and run it. After that, just find newly created service in NetworkManager menu and select the connection with name. That is it.