Howard, this latest error kind of sounds like a transient network problem. I would try a
few things, in this order of escalating severity.
1. Disconnect your Internet connection. This can be as simple as
ipconfig /release
ipconfig /renew
Or you can physically unplug the electricity from your network connection, then plug it
back in.
Then retry.
The idea is to refresh your connection with your ISP. Weird network glitches happen on
occasion. This is how I deal with those rare occurrences.
2. Delete cookies for the VDH web site. In Firefox, when you use the settings dialog to
delete cookies, it also deletes the disk cache entries associated with those cookies. If
you have any substantial amount of cache, this can be a lengthy & mostly useless
exercise. There is a Firefox add-on called Cookie Manager (not very imaginative but very
descriptive) that just deletes cookies without referring to cache.
Then retry.
3. Close all browser windows then retry.
4. I personally hate this advice but it might be indicated in this case. Reboot. Then
retry.
Separately, this other thread is kind of related to what you're talking about here:
https://groups.google.com/g/video-downloadhelper-q-and-a/c/W4gfxVmTGdY