I’m not sure whether or not SecurityTube - as well as YouTube - currently forces the use of HTML5 playback instead of Flash, but if I set Flash to Ask to Activate OR to Always Activate, Firefox does not use Flash on either of them at all and videos play back without issues. Therefor it may seem that there is something wrong with HTML5 playback in Firefox.

I suggest you temporarily remove Flash entirely and see if the videos play back successfully. If they don’t, are you viewing them when logged in to Google and if so, did you enable HTML5 playback here? Not sure if that should effect SecurityTube though. Does YouTube cause any issues and require Flash?

You can also test Firefox for HTML5 and other playback capabilities here.

Could you give a more specific link? A random one gave me an embedded YouTube player and finding a Camtasia video by trial and error seems unlikely.

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block (wanted) content (e.g. Adblock Plus, NoScript, Flash Block, Ghostery) then always make sure such extensions do not block (wanted) content.

• make sure that your extensions and filters are updated to the latest version

• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Thanks for the replies, sorry I've been out all day.

@Tonnes - I have *never* had a problem with youtube ( that I can recall ). Flash is set to 'Always Activate'. No, I'm not logged into Google - why do you ask?? Wow, that HTML5 link you posted looks extensive. It identified my system (FF 54 on W7). and then shows a lot of go / no-go items. Is that telling me what my browser can do (i.e. FF's capabilities), or is it including what I have/don't-have on my system (e.g. codecs, etc) ?? i.e. is it telling me something that I have to simply accept, or is it indicating that I can do (install) more to improve my capability??? Hope you understand what I'm asking ... It gives me a score of 474 out of 555 points. Good, bad, ??? I note that it says I don't have H.265 support, nor MPEG-4 ASP. Is that important?

@jscher2000 - The particular video is " http://www.securitytube.net/video/128 " . It's an IDA Pro tutorial.

@cor-el - Yes, I have AdBlock (not plus, haven't heard of that) but I had already tried with it in the paused state. When it was active, there was no Ad displayed above the Camtasia message - just a white space. When I paused AdBlock, there was an Ad displayed, but still the Camtasia message below it.

Thanks again...

I cannot view that particular video in Firefox, Internet Explorer 11 or Chrome. I get a 403 ("forbidden") response from the video server in Firefox and IE (not sure why the video isn't requested in Chrome?). I think that's why the page shows alternate content, which is completely unrelated to the reason for the problem.

I asked about YouTube because of the (assumed) settings page in the link posted above that could have any effect on affiliated websites that I thought SecurityNet would be one of, as well as enabling/disabling HTML5 playback that YouTube defaults to. As I understand it, the test page displays what a browser is capable of with regard to playback. I was a bit wrong above though - for a moment I though "The HTML5 player is currently used when possible" item had a tick box.

W7 and 54 show all 7 items checked here (as in this page’s first image), without the ability to change anything. Nevertheless, I don’t think they should affect preferred playback on SecurityTube, but the page at least indicates what your browser can do. Do you see that page as displayed in the second image displayed there?

My systems however also show the "update Flash" error, regardless of the Flash drop-down choice in Firefox’s Add-on Manager or having Flash installed at all. As the video link you posted also appears to be rather old (2011) and without looking at the page’s source, I assume it is not encoded to use HTML5 at all and Flash is required so you can skip the HTML5 part (unless the test page above shows other issues but regardless, it should be playable in Flash only.) Something goes wrong there in Firefox - as not entirely unexpected the video does display in IE because it still eats what it can get (wasn’t that an issue from years ago? ;) ) so what’s left is that despite the proper MIME being offered, which is required for Firefox and probably other browsers, there must be an error in the page’s code.

If you right-click on the page and Choose View > View Page Info > select the Media tab, and scroll down to the video swf file, you’ll see an object sized 0px x 0px. The Markup Validation Service reports a lot of errors for the page, but I’m not sure the exact reason shows up there.

You can have a look at line 496 in the page’s source by richt-clicking > View Page Source. Submitting it here is hard due to limitations of this forum’s software on quoting code. Note however that the error itself is not unique according to search results and the same question even was reported here on this forum, albeit answered with what is not likely to be the right answer.

Now I’m not a code or HTML guru, but suspect that either the conditional "if !IE" statement is outdated and should be fixed, based on info found in e.g. this question at Stackoverflow - see the "As of June 2103" comment, or perhaps some other part of that source, resulting in a permissions issue caused by the website. I’m not sure if that can easily be debugged using Firefox’s Web Developer tools > Inspector - I don’t use it that much, but some other HTML experts may be able to pinpoint the issue better. As for the message itself, it may just be a default message assuming Flash is outdated and in fact be misleading here.

My short answer (that may also save us some time ;) ) will probably be to ask the webste owner to fix this page to make it display in all browsers.

Hope this helps, and curious about the outcome. :)

I get the same error.

The Network Monitor show a 403 forbidden response for the Flash player.

@Tonnes - When I visit https://www.youtube.com/html5 I get the same as in your linked top image i.e. all 7 items ticked.

Reading your linked Stackoverflow thread, I see that there may be a problem with the [if !IE] when using IE 11, but I still don't see the connection to a FireFox problem. But then, I know next to nothing in this area.

To avoid too much futzing around the question of " Why " it doesn't work in FF (even though that was in my OP !), I simply copied the video link out of the page source, popped it into google and lo ... the first hit was the SecurityTube page / video 128, and the second hit was a YouTube video **that was uploaded by SecurityTube**. It works perfectly! As you say, it's probably an error in the SecurityTube web page. I don't immediately see any way of feeding back to them - the forum link is dead, the Tools link is dead... Maybe this thread is also, now..

Thanks for your help guys :)

https://support.cdn.mozilla.net/media/uploads/images/2017-07-07-00-54-29-21fd46.png