[Markvrb]

Samsung galaxy 5 android. No new installed apps very few apps. Don't use twitter app, google apps ( incl. Google play) or FB apps.

Upon downloading a twitter video using a downloader, the error message above occurs. This hapoens using several different downloaders, separate download occasions and after cache/storage cleaned and phone restart.

Help please. I can view video on Twitter and in downloader site pages, but when saved to download folder, can see video image thumbnail, but WILL NOT PLAY.
"FAILED TO PLAY VIDEO AN UNKNOWN ERROR HAS OCCURRED " box popup.

Help.

[B. Diddy]

Welcome to Android Central! Is this the S5 or Note5? What version of Android is it running?

What video format is the Twitter video in? Are you sure it's a compatible format for the standard video player apps?

[Markvrb]

Android 6.0.1
No apps used other than factory installed.
Use twitter and google with chrome 55 browser

vid format is .mp4 but so are all others i have downloaded.

Other vids play ok. Also thumbnail preview shows the video pic.

????

[B. Diddy]

Since it sounds like you're using a 3rd party downloader app, it may be an issue with that app. It may be able to download what it thinks is a compatible video, but perhaps something about it doesn't work with standard video players. Did it ever work before?

[Markvrb]

Yes, I've d/l vids before from twitter and can still download others but for some reason even though it is showing as an mp4, trying different downloaders sites, it's still not playing or subsequent download from SAME SOURCE (twitter user)
Obviously not personally knowing twitter user in question, i cannot find out what vid it is, but aren't the twitter vids all same format?
Terribly confused about the error because i can see the preview thumbnail and i can watch video from twitter or from the downloader site.

[B. Diddy]

It probably has to do with a bug in the downloading site, or perhaps Twitter changed something to prevent this from happening. From what I can tell, these downloading sites are not sanctioned at all by Twitter, so maybe they're starting to crack down on them. Their use probably also violates Twitter's terms of service: "You also agree not to misuse our Services, for example, by interfering with them or accessing them using a method other than the interface and the instructions that we provide."

[Rukbat]

.mp4 is an envelope, but the video can be any of a few formats, and can use any of a few codecs. Try installing VLC for Android and playing it in that. (If VLC won't play it, it's probably a bad fie - it plays almost everything.)