There's a lot of possibilities. You might try posting a proper problem report. To find
out how to do that, click this link:
https://groups.google.com/g/video-downloadhelper-q-and-a/c/BzPLK2YyL-s
You'll probably want to bookmark that for easy reference. In there, do a string search
on "problem report" which will offer you 2 links. Click both of those, read what you
find, & follow the instructions.
I suspect that the VDH queue stalls for reasons that are unique to your system &
transient. In most cases, clearing the queue & trying the downloads again will work. An
easy way to clear the queue is to reload the extension. Look for a reference to that
topic in the Table of Contents thread to find out how to do that.
Are you able to get a single download to work? Does the problem occur only if you queue
up other downloads when the first one is in progress? Have you looked in the Resource
Monitor to verify that, in fact, nothing is downloading? The Resource Monitor is a
standard, built-in part of Windows. If you're on another platform, something you will
tell us as part of a proper problem report, I would expect there is an equivalent tool.
In the VDH Settings, on the Behavior tab, there is a setting called Max concurrent
downloads. What value do you have for this?