I am having the same issue on my server

same on mine

Same, I can tame Equus fine but when I approach a Unicorn the feed prompt shows up but won't trigger. Tried kibble and carrots.

same here

No fix for this yet that I've seen, sadly. I managed to tame ONE, and all others won't do a thing. We have Immersive Taming mod too, and tried all methods of taming...none worked.

I asked about this on his discord because I noticed the name place holder (when using S+ scanner) for the unicorns is not the same as vanilla ones. He said that he's using vanilla unicorns but something is amiss.

I managed to tame them using ACM's Give ownership command