Why do two OpenVPN sessions from the same network kill each other?

Question

openvpn

Good afternoon!
There is a standard installation of OpenVPN 2.5.2 from Vultr on Ubuntu 18.04 (I took it ready, because my hands are still crooked). There are no paid licenses installed, so only two connections are possible at most. No changes were made to the finished assembly, except for:
1) Two new
logins are configured 2) Routing = "Yes, using Routing" is set in VPN Settings and a grid equal to the general pool of VPN addresses is registered in private subnets
Result: while two connections come from different networks, everything works fine, but if both computers are connected from the same subnet (due to the NAT router), then both connections hang after 10-20 seconds. In the management console in the list of connections, they are visible, but the packets do not go: formally there is a connection, but the ping grows to 20 seconds, and sometimes everything freezes.
This situation is not displayed in the logs at all.
Question: what am I doing wrong? :)

Answer 1

Never had to deal with such a configuration.
Usually, when you need to connect several clients from the same network, they allocate a separate computer, which will be the only VPN client, and the rest go through it.

Answer 2

For example, you can do like this:

<div>
  <form name="publish">
    <input type="text" name="message" placeholder="введите сообщение"/>
    <input type="submit" value="отправить"/>
  </form>
</div>

When we click on the send button, we collect the data. With the help of this JS code for example

document.forms.publish.onsubmit = function() {
  var message = this.message.value;
  console.log(message)
  return false;
};

Or, as written above, you can do it:
But there are some nuances
Reply to your comment:
If there is no button in the form, then you can use the onchange event.
For example, here is a form without a button with an onchange event that calls a function in JS:

<div>
  <form name="publish">
    <input type="text" name="message" placeholder="введите сообщение"/ onchange='eventForm(this.value)'>
  </form>
</div>

<script>
function eventForm(value) {
  if (value == 'test') {
    alert('Вы ввели то что нужно')
  }
}
</script>

You can see details about the onchange event here: https://learn.javascript.ru/events-change