Playing DTS doesnt work

hi

just bought iXpand USB3 - and i’ve tried to move a 5 gigabyte mkv clip but i’ve got an error msg  that said “the file is too big” 
so i format the DOK to exFAT.
after that i’ve tried to play MKV clip with DTS sound and it doesnt work at all … 

can you assist me  ? 

he app does not support dolby audio codecs

http://kb.sandisk.com/app/answers/detail/a_id/18851/ 

The (iXpand and Connect) apps do not currently support certain audio / video formats, such as those encoded with AC-3 (Dolby Digital) codecs. In some instances, you may be able to select the file and use the “Open in” feature to use other apps on your device that support such formats to playback these audio / video files.

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