What's happening .. something went wrong?

What’s happening … something went wrong?
I have been using Plex for nearly 5 years …
Recently, about a week ago - things have seems to be broken on couple of devices?

My partner’s tablet is old - Lenovo Tablet A5500-F (it’s perfectly fine for watching video via plex).
The subtitles was working fine but then it wouldn’t run external subtitles anymore. I have checked on other tablet (Samsung Tablet TAB SM-T310 - version 4.4.2) - Video isn’t smooth playback but subtitles works with no issues - it’s why she got a new Lenovo few years ago (purely for plex only).

I’ve checked subtitles on PC, Google Pixel XL, Nvidia Shield TV - the subtitles works.
What’s weird is, when I installed Plex Client on a different laptop - the subtitles does not work?!? - I find that very odd.

It can read internal subtitles no problems, but i want to use external subtitles with my own style .ssa (not .srt)

All this week, my partner have been nagging at me trying to fix this thing, I have been looking for solution, etc… but unable to find out what’s going on :frowning:

Nvidia Shield TV - Version 6.3, Plex - I use it every day as it’s my main device - always update to the latest
Samsung Galaxy Tab SM-T310 - Android : 4.4.2, Plex Version : 6.15.2.4143
Lenovo A5500-F - Android 4.4.2, Plex Version : 6.15.2.4143
Plex Server - Windows 10 Pro, Plex Server Version : 1.12.2.4929
Acer Laptop - Windows 10 Home, Plex Client Version : (unable to check as my partner took it with her atm but will update this asap)

Hope someone can give me what I’m missing?