Theo:
Is it free or do we have to pay to see Sangmin Dinneaw?
It's exclusively on iQiyi, which is a paid subscription platform that has been getting quite strong for BLs.
When I started watching BLs, Viki and Gaga were the dominant subscription platforms (i.e. beyond Youtube), but I find myself watching iQiyi a lot these days. While Gaga is probably best on content and Viki best as a technical platform, I'd probably put iQiyi as #1 these days for a combination of both, i.e. good BL content, plus the platform works well. Sadly, Viki seems to have slowed down on licensing new BLs.
My only gripe with iQiyi (as also with WeTV) is that quite a bit of content is geo-restricted, so I frequently need to use VPN to watch what I want, and even then I often need to trick it by calling up the video by a link, or first finding the video in incognito mode, then starting it before logging in.