Oracle - Follow all the instruction but the clients cannot connect to the server

Hi there, I install Wireguard on Canonical-Ubuntu-20.04-2021.12.01-0 Oracle VPC by using your instruction. I believe that I got no error message during the installation, but the clients (on Windows) somehows cannot connect to the server. Any idea?

Someone had a similar question on Reddit today.

Did you try this? https://reddit.com/r/WireGuard/comments/rj3u9i/wireguard_on_ubuntu_oracle/