Are you using a M1 or M2 Mac? According to Fenics :: Anaconda.org, there is no available package for aarch64 macos.
I’m not a Mac user myself, but you might find some help following these topics: FeniCs on Apple silicon M1 Legacy FEniCS 2019 on Apple Silicon
For instance, you could try either using docker, compiling from source, or using dolfinx which has conda images for aarch64 macos.