Subtitles not working on video.js player for Wordpress

I add video.js plugin to wordpress and insert the video into post with this shortcode

[videojs mp4="https://example/video.mp4"][track kind="captions" src="http://localhost:8000/wordpress/subs/sub_mac.vtt" srclang="en" label="English" default="true"][/videojs]

The CC button is showing but can not activate the captions. Please help! Thanks

via Chebli Mohamed