After installing Fedora 33 Since it is a test, promote it to root
sudo passwd root su yum install -y xl2tpd NetworkManager-l2tp NetworkManager-l2tp-gnome
Fedora 33 seems to use libreswan for ipsec, eliminating vulnerable algorithms. It seems that the excluded algorithm is used in MS compatible L2TP/IPsec, so change it to strongswan.
yum remove libreswan yum install -y strongswan
Reference information 6 VPNs https://opensource.com/article/18/8/open-source-tools-vpn https://www.tecmint.com/setup-l2tp-ipsec-vpn-client-in-linux/
MS Azure L2TP configuration https://network.yamaha.com/setting/router_firewall/cloud/microsoft_azure/setup_rt
Fedora & Algorithm https://ask.fedoraproject.org/t/cannot-connect-to-vpn/5602/42