The remote host forced the shutdown of an existing connection (error 10054)

[Paket236]

When I run 5 instances of my program, interacting with different discord bots (1 instance = 1 bot), everything works fine. As soon as I launch the 6th instance, I receive a message once a minute (or 2 minutes) on all instances (time is a little different), as in the screenshot. Reproduced always. Maybe it will say something, but I run instances in Sandboxie. Minimum traffic consumption (0.01 Mb/sec). Processor is loaded stably at 70-80%. What could be the problem and how to fix it?

[Paket236]

There are suspicions that this is due to the fact that I use VPN. Without it, there is no problem.