Please try the following steps to diagnose your problem.

Monitor instance color boxes

The colors of the instances boxes can give you an insight of what your instances are doing (e.g., buffering, watching). ⬛🟨🟩
You can force instances to restart or take a screenshot, too. See Advanced-features-and-controls.

Take a look into the logs

When you use the tool, a log file named "ctvb.log" is created in the root folder. Open it with a text editor and check

1. Are there any error, and what could they mean @Dr.Google?
2. Did my instances start, restart and stop correctly?
3. Are my instances using the correct proxies from the proxy_list.txt?

The logs get overwritten the next time you start the tool.

Take and inspect an instance screenshot

Take a screenshot of a running instance by using 🖱️ Left click + CTRL on an instance color box. The screenshot is saved in the root folder. Open it and check, if you can see the stream working correctly in the screenshot.

Start a headful instance and watch

When headless is turned on, you cannot see the Chrome instance windows. Try turning it of / start a headful instance and watch what the browser is doing. Did it reach the stream, get stuck anywhere, or did it time-out?

CPU and RAM usage

Check the built-in % CPU and % RAM usage. Are they close to 100%? Is one bottle necking the other? Are there usage spikes?