can not play a video on IE11 but can play it with firefox

Hi all,
i use mobile app. to upload videos and see them on the web.
as i wrote i can not play video on IE11 (on 2 win 7 machine) but can play it with Firefox and in my iPhone as well.
the error is "error loading media the file could not be play". i should mention that error message did appear once or twice with Firefox , but play fine 99% of the cases.
i think the file is mp4 encoded.
i goggled a bit but no solution...
all flash/you tube can be seen both browser, only specific videos from the app are not.
browsers and flash player are updated. all IE11 set to default.
i cleaned history cookies caches -did not help.
no popup blocker is on IE11
what cause the problem?/how can i solve it?/ whats wrong on IE11?
HTML5-related?
e.g-link to a video (it takes few seconds to load )
Video Mail
can somebody with IE11 see the video?
Thanks!

See Posts #14 & #15 in this thread. Ignore the brightcove suggestion because the video does not use that platform.

IE11 & Adobe Flash

So as a test try disabling ActiveX Filtering. Exit IE and relaunch to test the video.

thanks Callender
-i unchecked ActiveX filtering on internet tab (not trusted site as in #15) and it did not help .
got the same error...
-also tried to add the site

http://email.mailvu.com

in trusted site +unchecked ActiveX filtering, and it did not help.
any other suggestions?
the video link above starts :

http://email.mailvu.com....

Okay I will install flash player for IE and see if I get the same problem.

Well I tried everything that I could think of but could not get it to play.

thanks again,
interesting issue indeed...
FF-video seen fine
IE 11- not
if not security issue, i think it may related to the video format ?
interesting to check it with previous versions of IE /win.XP
I WROTE THEIR SUPPORT AN EMAIL, 2 TIMES AND THEY ARE NOT ANSWERING yet ...

I WROTE THEIR SUPPORT AN EMAIL, 2 -3TIMES
untill they answered - they send me the link below and now i can see the video on IE11.
http://webtest.mailvu.com/msg/i617b0388ccc4432ab1bbc55e81e62c71

Video Mail

he added "webtest" to the address.
here is the original address(can be seen in Firefox BUT not on IE11
http://mailvu.com/msg/i617b0388ccc4432ab1bbc55e81e62c71

Problem is that other videos still canot be seen from the above app. in IE11
i tried to add "webtest" to the address -but i think the support only made experiment
with the discussed video above only.
1-do you have any idea how to make others app. videos seen on IE11?
2-any idea what the change "webtest" to the address caused so i can incorporate it to other videos?
what trick is hiding behind the "webtest" added address ?
Thanks

I can see differences in the code for each page. Basically extras have been added to the test video page but I can't figure out the important lines. I've attached text files so that you can see the differences.

Original.txt

Test.txt