Maybe, but it's definitely not your fault if so. That feature is really primitive / finicky in it's current state. So, the feature is designed to work with a pre-sorted collection of subtitles, which is accomplished with the Organize Subtitles utility. If you'd like a pre-sorted list of around 26K subtitles to try out, I've uploaded one here:
Subtitles.v2.zip
Download and unzip this, then go to JavLuv's Settings and point the Subtitles folder to that location.
Now use CTRL-A to select all your movies in the browser view. Right-click and select Find subtitles, and choose a destination folder to place any located subtitles in that match up with your collection. Note that any movies with subtitles already found in it are ignored. The result may be no files if none are found, or a collection of subtitles if any ARE found. It's up to you what you want to do with them after that.
If you add subtitles to your movies, I think recanning files should work to pick them up. You'll see a small screen icon below and to the right in the detail view, like you can see on the first post in this thread.
Sorry the feature is in such a primitive state. At some point, I'll make a custom dialog box to show progress and more detailed results. For now, it is what it is.
If you want to tell for sure it's working, you can download one of the movies I subtitled myself, since I know for sure those are in the collection. Or, you can find another one and use the Subtitle Organizer tool to add it to the collection yourself (that's what it's for, after all).