FG mishap on suspected url trickstery

[Barvinok]

Hi.

For years, FG has been my #1 tool to handle online videos the way I want. Yet it trips over sometimes.

Ok, so I use FF 43.0.4 and FG out of AMO. Then this site [WARNING: porn site!] has a video I'd like to download: www dot guarrasdelporno dot com / follando-amigas-hija-mientras-duermen / (remove spaces and replace "dot" with dot, thank you antispam).
There FG would download a 162 byte file with .mp4 extension having valid HTML markup inside saying "404 not found". So the server is playing smartass on me.
Trying recent development FG did not help.
Is there a way to make it work as intended?

[therube]

Videomega.

(Without looking at the particular clip in question...)
I've hit that one before, & I'm not sure what to do about it?

I expect (& not that I know anything about these kinds of things) that immediately after the first "hit", it invalidates the URL, such that any other attempt yields a 404 or similar.

Not too long ago, I did a quick search, but what I found was all dated (at that time) & no longer applied to whatever it is that they are doing now.

[therube]

You may have some luck using (Browser Built In) rather then any actual download manager.

May also help if you were to "block" stuff, say using NoScript per chance. Stuff like FRAMES, & maybe "media", so that you get a placeholder rather then actual playback. Thinking grabbing the placeholder is less likely to invalidate the URL.