Hi!
I believe your configuration is correct, I see results based on tags. Let’s see if we can make an adjustment here.
First, let’s make sure that the search in tags is indeed enabled: https://i.imgur.com/9qlzvam.png
From what I can see it is, but still it’s worth checking.
Then, the plugin by default sorts the results based on relevance, but in your case this might not be the best option for you. On the General Options -> Ordering panel you can change that. I recommend trying the following configuration: https://i.imgur.com/g58BvgX.png
On the downside, this will ignore relevance calculations, but any matches will be displayed, and sorted by the latest first. My guess is, that the plugin was matching the expected results by tags, but because of the high number of matches and the relevance ordering, it might have been cut off of the list.
You can improve the matching even more by enabling exact matching. This makes sure that the search phrase matches as it is typed in, anywhere in the chosen field: https://i.imgur.com/Szyq18M.png
It’s a matter of preference, but definitely worth trying, to see how it changes the outcome.
I hope this helps!