We have a system that uses a few vmix instances to record a group of NDI HX cameras and grab a few snapshots. To trigger the start and stop of the multicorder and grab the screen shot we use a telnet sender to send the TCP API commands. This has been working well in multiple locations with a dozen vmix PCs for nearly 2 years now.

Except for one system which started randomly having issues about a month ago. This PC would fail to stop a recording or take a snapshot. Usually once a day. It took awhile to figure out what was happening, I had to modify our application to send me an email when it started happening so I could investigate.

vmix would otherwise appear to be working normally and could be interacted with, so it wasn't like it was frozen. The recording could be stopped and started manually, and snapshots still worked, but when the telnet sender tried to contact vmix and waited for the version string response, it got nothing in response. Restarting vmix would get it going again.

There are two identical PCs running vmix. They both get the same commands at the same time. The second PC doesn't have this issue. Nothing has changed with these pcs since they were installed about 6 months ago. They reboot nightly and have been working every day non-stop for a year before this.

system specs

Win10 LTSC 2021 on a Ryzen9 mini PC.
vmix Max 27.0.0.69 at the time of the issue. Since updated to 27.0.0.81.