Load Display subtitle track with mejs?

Anyone gotten subtitles to correctly load with mejs?
i cant seem to get the subtitles to show.

https://vuflix.com/de-broglie-interview-1967/

i have a (VTT) plugin that allows me to add subtitles and the track is being correctly added to the video element. but still it doesnt load the track on a layer (the layer seems to maybe be disabled).

i can manually add another link to open a new window with the titles in it but i just want the live subtitles to show in synch with the timestamps.

edit: this filter might also help, but im still not sure how to get the track displaying.

also tried to get a jQuery subtitle working with: http://v2v.cc/~j/jquery.srt/
but i couldnt get the element dynamically added properly either.
would be good if subtitle support was baked into wordpress default video mejs.
if anyone knows a good plugin that works with Videobox please let me know

@jsky it looks like the uploaded subtitle XML file contains an error: