I can't add .srt subtitles

[Juan]

When I add .srt subtitles to a .mp4 file I can see the time but when I save the .mp4 file the time subtitles turn 0:00:00.

And subtitles don't work.

macOS 10.14.3 Subler 1.5.13

[Juan]

I have discovered the problem. All the original subtitle file was badly formatted, the subtitles had no duration:

Example:

00:01:44,132 --> 00:01:44,132

Thanks and apology the inconvenience.