Could you provide the screenshot of that error.

Update your firefox to the latest version of Firefox 26.

• Firefox Menu > Help > About Firefox

Download the beta version of Adobe flash player.

• http://labs.adobe.com/downloads/flashplayer.html

I actually have Firefox 27.0.1, and updated to the latest version of Flash.

On another computer running Firefox 27.0.1, the same problem is occurring.

Hello,

Some problems with Flash video playback can be resolved by disabling hardware acceleration in your Flash Player settings. (See this article for more information on using the Flash plugin in Firefox).

To disable hardware acceleration in Flash Player:

1. Go to this Adobe Flash Player Help page.
2. Right-click on the Flash Player logo on that page.
3. Click on Settings in the context menu. The Adobe Flash Player Settings screen will open.
4. Click on the icon at the bottom-left of the Adobe Flash Player Settings window to open the Display panel.
   
   The image "fpSettings1.PNG" does not exist.
   
5. Remove the check mark from Enable hardware acceleration.
6. Click Close to close the Adobe Flash Player Settings Window.
7. Restart Firefox.

This Flash Player Help - Display Settings page has more information on Flash Player hardware acceleration, if you're interested.

Does this solve the problem? Let us know.

Tried that too, and no difference.  :)

I'm not sure what you mean by "refreshed" the browser. Did you re-run the installer, or did you use the Reset feature, or was it something else? (Not that I'm suggesting any of those things at this point, just want to understand what you've tried.)

Meaning "restarted" the browser.

You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History > Show All History" or "View > Sidebar > History") or via the about:permissions page.

Using "Forget About This Site" will remove all data stored in Firefox from that domain like bookmarks, cookies, passwords, cache, history, and exceptions, so be cautious and if you have a password or other data from that domain that you do not want to lose then make sure to backup this data or make a note.

You can't recover from this 'forget' unless you have a backup of the involved files.

It doesn't have any lasting effect, so if you revisit such a 'forgotten' website then data from that website will be saved once again.

Thanks. At this moment the issue has resolved, but in the future this will be used if the problem reoccurs.

I see this error if I leave the page open in a tab and let Session Restore reopen this page on a next start. It is always sufficient to refresh the page (F5) to clear this error message.

(Youtube uses Dynamic Adaptive Streaming)

This problem drove me nuts, while re-imaging a system for a friend. While testing the refreshed system, I found that all videos worked fine from every website I tried, except YOUTUBE. It would start to play for about 2 seconds, then "An error has occurred, try again later.", and the old snow screen effect. I finally ran across a post from last fall, and it worked great. I did not have to install the Youtube-Center plugin script mentioned in the link, because my issue was related to not have sound connected. I just plugged in some speakers, and presto Youtube started working great. Go figure... Here is the post.

This had been happening to me too for ages and nothing made a difference... until I read a few lines on a forum somewhere that solved it in an instant...

YT started using Dynamic Adaptive Streaming over HTTP (dash) a few years ago and this is what's causing the problems. You can download a script called Youtube Center that allows you to turn off dash : https://github.com/YePpHa/YouTubeCenter/wiki

Or, as I found, you can simply plug in a set of headphones into your pc (or use a set of speakers) and that ever present and hugely annoying "an error occurred" message will be gone from your life forever.