Subtitles not showing using WebVTT

You use the incorrect time-stamp format. There should a . (dot), after the second value.

It should be like this: 00:00:00.000 --> 00:00:10.000

Browsers do not support that feature locally

Except Mozilla Firefox 66.0.2

It doesn't work locally, you need to run it on a server.

I had the same problem you were having.

The problem is that Chrome has a security feature that does not allow files to run local files in Chrome.

The solution is to run Chrome with the allow local access flag. The link gives instructions for each OS.