Why is the reference image greyed out in Photoshop Beta Generative fill?

I am using Photoshop Beta v 26.11 on my Windows 11 PC. I would like to add an object to a portion of my photo using a reference image for Generative Fill. In the past, this has been no problem. After making my selection, I simply click the reference image icon in the Generative Fill tool box that pops up and upload the image. Today, however, that icon is greyed out. I hover over the icon and it tells me that to activate this feature I need to be using Firefly Image 3 model. Fine, but I am already using that model. What is going on here and how do I fix it? Thanks!