Turn off add blocking on this site. VSys Live never shows advertisements - it's not that kind of site! - but some ad blockers may disrupt requests made by the browser for required files, which in turn can cause VSys Live to not work properly.
Try another browser - Chrome is by far the most stable and least likely to have issues.
Try another computer, especially if you're using a mobile device.
Chrome can provide great diagnostic information about its interaction with websites. With the browser open and on the application submission page, hit the F12 key. This opens up the diagnostics console. Other browsers such as Internet Explorer, Edge and Firefox offer similar tools.
There's a lot going on here:
At the top is the timing of the various requests sent by the browser.
In the middle is a list of all of the detailed requests and responses (you can click on any of these to get even more information). Scroll through this list and look for any items in red: if you see one or more, that means that a request made by the browser was returned with an error.
At the bottom is the console. The console is showing some logging messages, but no errors: and that's good.
If we saw any errors here - either in the console or in the list of loaded URLs - get a screenshot and send that to the VSys One support team. It's important to note when the application was submitted: an accurate date/time for this can make a big difference in being able to find useful information in the system logs.