It is unfortunate that the automatic update to VDH occurred in the middle of your
download. You should go into the Firefox settings for Add-ons & turn off automatic
updates for VDH. You can update VDH whenever you like, on a schedule that is convenient
for you, by using the link on the home page of this forum. That link & a number of
others are at the top of the page in the area your eyes usually skip over. Don't skip
over it. Read it. There's bold characters there to catch your attention. Let them
catch your attention.
While you are reading that, notice there the description of what constitutes a proper
problem report. You have not provided that. We need release numbers, not "latest" or
"up to date." We also need specific URLs, not just the name of a web site. The error
message you posted is actually not particularly useful in diagnosing your problem. The
URL in it is not usable by anybody, plus it's just not enough information. The URL of
the web page where that video is hosted is useful.
When VDH does not successfully complete a download, which is what happened to you, there
is nothing else to do but start the download over from the beginning. But in your case,
it wasn't simply a failure to download. VDH got updated. I would suggest you close all
your Firefox windows, then come back to your web page & try the download again.
Meanwhile, there is an extra step that you must perform. I talk about it in this thread
that I updated earlier today:
https://groups.google.com/g/video-downloadhelper-q-and-a/c/MZOSvO7h_vo
Follow the advice I posted there. That may or may not improve things for you, but it
can't hurt to try it.