In the server settings need to enable routing of packets.
nano /etc/sysctl.conf
allow exchange between the network interfaces, add
net.ipv4.ip_forward = 1
Taken from here
www.unitec.com.ua/nastrojka-pptp-vpn-na-centos-7
Firewall -
firewall-cmd --permanent --add-masquerade
firewall-cmd --zone=public --add-port=1723/tcp --permanent
firewall-cmd --permanent --direct --add-rule ipv4 filter INPUT 0-p gre -j ACCEPT
firewall-cmd --permanent --direct --add-rule ipv6 filter INPUT 0-p gre -j ACCEPT
firewall-cmd --reload
Taken from here
https://sysadminblog.ru/linux/2018/07/11/prostoy-p...
Could not tarffic to transfer, now everything is OK - Magnolia.McKenzie commented on April 19th 20 at 12:07