Asking for a WPA2 username

I’m trying to revive an old Mac Mini that’s on Mountain Lion OS.  I had no problem joining my old WPA2 WiFi network. But when I tried to join my new Eero network, instead of just asking for a password, it says it requires WPA2 enterprise credentials, which has a password AND a username.

My understanding for forum posts is that Eero doesn’t support WPA2 enterprise, so why would the computer think that Eero is using WPA2 enterprise? Would anyone have suggestions on how I could get this computer to work with the Eero network?

Thanks!