WHY does the VPN interface go to sleep?

Question

VPN

There is a configured VPN channel between two servers (1 and 2). VPN WireGuard is configured according to the manual HERE THIS After the time expires, the channel goes into sleep mode. If you ping from the server 2 by 1, then the packets do not go through at all. If you ping from the 1st to the 2nd, the channel works for a while, and then if there is no traffic again, it ceases to be available until the second ping from server 1. Server 1 is organized from a regular home P. Of course, I solved this problem through cron. I ping from server 1 server 2 every minute. But I think it's a crutch.
PS I bought a VPS installed wireguard there and configured everything exactly the same. And it works flawlessly. Well, server 2 works fine too. What could be the problem???? How to disable the Gree feature so that the network interface does not go to sleep?
PS In Desktop Ubuntu you can find and disable power saving. But what about Ubuntu Server where to look, where to dig,

Answer 1

So look at the energy saving mode in ubuntu ...

Answer 2

The problem, with a high probability, is the UDP connection timeout on your home router. You need to either increase it, or somehow configure keep-alive in the VPN.