MP4 files won't play. ".mp4 files are supported but something went wrong."

Dear All,

I fixed the problem via making the videos shorter. As long as they are less than 40 minutes this does not happen to me anymore. How long are your videos guys?

Thanks for the observation Grigoryeva.  However it won't help in my case.  My error-free video is 24 seconds duration, the one that stalls midway through is 18 seconds, and the one that throws the error is 26 seconds. 

I wonder if, when you shortened your videos that you used different settings ?  Or simply reloading it might change the behaviour.  However, all that should be irrelevant.  An mp4 that successfully plays in a standalone player should play in the (Dropbox) browser window. There are reports of videos that used to play no longer playing.  In any case, why should we have to trouble shoot what is obviously a problem of DropBox's own making ?  Sounds like all DropBox have to do in the short term is down-rev the relevant parts of their code to a version that works while they go about looking for (and properly testing !) a permanent fix.

I fully agree that this should be fixed and FAST! These days there is a huge need in streaming lectures, tutorials, other materials. Since I saw that this issue appeared to me a few times and this small fix worked, I just mentioned it here. Another thing I tried was to re-export again my video in Quicktime. Unfortunately, I did not change any settings whenever I re-exported or made them shorter. This gives me headache too as I need to check the links each time and to waste tons of time for things which should be automatic.

Same problem: can't view mp4s online. Which means my friends can't see my videos. Solutions?

Hi,

I too am having this issue. We've been using dropbox to share video tutorials with our students as other tools have size limits that are too small. Most of our videos are 5-15 minutes long and have been working flawlessly over the previous 2 weeks. Today, however, students have been unable to watch the videos. The video file works fine and I've tried reuploading it to get a new link.

Our current work around is for students to download the video and then play it but I'd really like to avoid having to do this for every video. We do a lot of the video recording on iPads so they are automatically .mp4 and converting them to another format would be another hassle i'd like to avoid so I'm hoping there's some other solution to this problem so links to the video work in the browser.

I'm not sure why it's stopped working as nothing has changed in the way we've done things.

Same issue. Started this week after a few years of using Dropbox. Have tried re exporting the video several times and am still receiving the same .mp4 playback woes as many have stated. I'm looking like a real flopper to my client currently.

Just like that today all my .mp4 files are working fine. Hope its the same with everyone else.

Yep,  my one mp4 that previously threw up the ".mp4 files are supported but something went wrong." error now plays to completion.  However, the video quality is really low. Like about hald the resolution of the same video when played with quicktime player and with a lot of what look like jpeg artifacts when the compression is too high.

So progress but not the full solution.