Someone in the group posted something genuinely useful. A fix for the same fault your car has. A technique demonstrated properly instead of described. A local seller showing what the thing actually looks like.
You copy the link, paste it somewhere, and the page tells you it cannot read that address. Nothing is wrong with the link. Posts inside a closed group are structured differently from public ones, and a lot of tools were only ever taught to read the public kind. FvidGo Facebook video downloader handles them, and the only condition that matters is the obvious one: you have to be a member who can already see the post. What follows assumes that is true.
FvidGo

FvidGo covers everything published on Facebook rather than a shortlist of post types, and content inside groups you belong to is part of that. The useful way to think about it is that the question is never “does this tool support groups” — it is “can you open that post yourself”. If the video plays for you in the app, it is reachable. If you were never admitted to the group, no tool changes that, and none should claim otherwise. That is the test to put any Facebook video downloader through: not what it lists, but whether it opens what you can already open.
Group posts are also where parsing gets tested properly. Members re-upload things constantly — a clip forwarded from somewhere else, a video attached to a comment rather than a post, a re-share of a re-share — so the addresses are far less tidy than a page’s own publishing. Claiming support is easy; actually resolving those links is the part that decides whether you get the file. A verdict arrives in seconds either way, so on the rare post that genuinely cannot be read you learn that immediately rather than sitting on a stalled page wondering whether being in a group is what broke it. A Reel someone re-shared into the group runs on the same route, so a Facebook Reel downloader is not a separate errand.
There are four quality steps to choose from — 1080p, HD, SD, 360p — and group content is a case where taking the top one first is usually right. Anything inside a closed group can disappear without warning: the person who posted deletes it, an admin clears out old threads, the group changes its settings. You often get one attempt at saving something, so it is worth spending the extra space rather than planning to come back for a better copy that may not be there.
None of this involves signing in. A private group is private precisely because it is limited to the people in it, and saving something from it should not mean typing your Facebook password into a second website. You already have access through your own browser session; the link is all that gets handed over. That is the whole condition on a Facebook private video download: your own access, not a password you give to a site.
Copy the link from the video inside the group, paste it at fvidgo.com, pick your quality, and download.
Snaptube

Snaptube is an Android app. Its reach is over a hundred sources, quality runs as high as 4K, and it writes MP4, MP3 and M4A, with a player included so saved files play without leaving it. You install it from the official site, or from your handset maker’s own store if your phone came with one; Google Play does not carry it.
Its relevance here depends on how many groups you are in and where else you collect things. People who save from several communities usually are not doing it only on Facebook — there is a forum clip, something from a messaging app, a video from another network entirely. One app covering 100-plus platforms handles all of that rather than needing a separate tool per source.
Choose it when you want what you saved to stay in one place and play there. Downloads land in its own library, so the group video you kept in March is still labelled and still playable in the same app months later, without going through your gallery.
The distinction to keep in mind is the device. There is no iOS build, so an iPhone or iPad owner stays with the browser method above — which is also the route for anything you can only reach through a session you are already signed into.
FDownloader

FDownloader at fdownloader.net is a web tool needing no install and no registration, with a dedicated page for private videos alongside its ordinary one. It reaches 1080p and can convert to MP3. The page carries advertising.
Use it as a second opinion when a particular group post will not resolve on the first attempt — having a purpose-built private entry point makes it a more sensible retry than a general public-video tool. Bear in mind that a dedicated page is a statement of intent rather than a guarantee for every link, so if it comes back empty, go back to the main method rather than working through a list of similar sites.
FDownload

FDownload at fdownload.app is the other web tool here with a private-content page of its own, claiming support for closed groups and pages, and it also handles public video, Reels, Stories and MP3 extraction at up to 1080p.
The two are close enough in design that they are best treated as one option with two addresses rather than two independent choices — if a link fails on one, the other is worth a single try, not a systematic second search. Worth knowing too that its traffic and search ranking have been sliding for several months, which is the kind of thing that eventually shows up as a site being slower to fix when Facebook changes something. Fine as an occasional backup, less so as the tool you rely on.
FAQ
Can I still download something after I leave the group?
No. Once you are out, the post is not visible to you, and a downloader only ever sees what your own access allows. If there is something you want to keep, save it while you are still a member.
Will the admin or the person who posted know I downloaded it?
No. Facebook does not notify anyone about a download, and there is no entry in the group for it. What people can see is ordinary post activity — reactions, comments, shares — not files saved to your phone.
Why do some videos in the same group work and others do not?
Because the audience setting belongs to the post, not the group. A member can share something with a narrower circle than the whole group, and a video originally posted elsewhere carries its own restrictions with it. If one fails while others succeed, that is almost always what is going on.