Problema resolvido, esse cara me deu este link
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
modprobe nf_conntrack_pptp nf_conntrack_proto_gre