Install Subscene and or OpenSubs addons. Can be found in the official Kodi repo.. I keep both just in case.. Most popular addons prefer to use Open Subs in their addons.

I see.. Means the title's subs aren't available on the service. Prolly cuz not popular enough for someone to go through the trouble of subbing it.. Yeah, OpenSubs requires either free or paid membership. You can sign up for a completely free one on their website. Which is down at the moment. .Addon may be affected.

u mean tvb dramas in icdrama?

the videos there are either chinese or eng hardsubbed.

u will not find soft subs in opensub or other providers.

the way online subtitles work...

.. the video must be done with a recognizable title; someone makes a sub corresponding to that title, list it in one or more providers.
.. newer, more popular videos, chinese or eng or korean... subs already exist from original, e.g. DVD or BD... someone just need to list it with a provider.
.. eng videos are watched worldwide, plenty of people list the subs on various providers, various european, middle eastern, asian languages.
.. these subs, u can access direct on the provider sites or via kodi.

.. chinese tv videos most popular in china, don't need eng subs; hk/canto/tvb not popular worldwide; old tvbs least popular - few want to make eng subs.
.. typically, china-taiwan-hk tv videos come with chinese subs only - for those who can't converse in but can read chinese.
.. the most popular chinese tv videos, blockbusters, e.g. three kingdoms, condor heroes... some fans make own eng subs and hardsub their own video version, e.g. fansub.
.. whether icdrama or other sites, u get what u get - hardsub or no sub, chinese or eng, depending on old or new, popular or not - that's it.

AVFAN explained well.. So what he says..

Opensubs still works great without their VIP membership. Both paid and free members get access to all subs available. VIP mostly is to browse ad-free, get direct download links right on the search page vs navigating the various funny ad links on the website and no ads within the srt file itself.. With the Kodi addon, you should be fine with free alone. Though, it's good to support such endeavors as they work hard to make our sailing across the high seas more pleasant.

I googled BTScene and it's a torrents aggregator.. Not subtitles website. For me, over the years, I've only needed either subscene or opensubs to fill all my needs. But then, I don't watch tvb dramas.. So different case. The Asian contents I watch all usually come with English subs included..