Oddity: MF_MEDIA_ENGINE_ERR_SRC_NOT_SUPPORTED error while playing back .WMV files

I'm getting an error while playing back a few movie trailers fetched from a web service.

The error is thrown on the MediaElement's MediaFailed-event:

MF_MEDIA_ENGINE_ERR_SRC_NOT_SUPPORTED : HRESULT - 0xC00D0035

What I've found so far is that it might have something to do with transcoding or the likes - so here are some facts about the file:

Size: 13.1 MB
Frame width / height: 640 * 360 px
Data rate: 704 kbps
Total bitrate: 800 kbps
Frame rate: 25 fps

Note that this happens only with a select few videos (that used to work a few days ago, but the data might have been changed since last test run). Another video - that plays perfectly - has the exact same specs (~ the same size), but with height 274 px.

Both videos play perfectly in Windows 8's media player app.

Any ideas as to where to start on this one?

SOLVED: After checking out the HRESULT code (0xC00D0035), I found out the meaning behind it:

0xC00D0035
NS_E_SERVER_NOT_FOUND

That made insanely much sense - as my REST-API gave me some inconsequential data (some had a slash, some had not). Basically - my source URL was sometimes wrong! :-)