Issues playing some files on iPad Air 2

Hi,

I have an issue playing some files on my iPad Air 2:

Matroska: 1.56 Gib, 55mn 42s
1 Video stream: AVC
1 Audio stream: AC-3

Overall bit rate: 4011 kbps
Writing application: Lavf56.40.100
Writing library: Lavf56.40.100

English: 3548 kbps, 1280*720 (16:9), at 23,976 fps, AVC (High@L4.1) (CABAC / 5 ref Frames

Audio: 384 Kbps, 48.0 Khz, 6 channels, AC-3

I works when using Buzzfeed HD

Any idea what the issue might be?