Why won’t my Eevee evolve into a Sylveon?? (Read body text)

I started playing like a month or two ago. I set my Eevee as a buddy, it is also a great buddy. I have enough stuff to evolve it. I set its name as Kira and i can see the silhouette, however, when i try to evolve it, this message pops up. Why? Is there something im doing wrong or is this some sort of bug??