HFSS port 'Port1' does not have a valid reference plane above or below it
I'm relatively new to HFSS myself, so keep that in mind.

When I had a similar error with one of my designs, it was because I didn't define a ground plane in the wave port definition under excitation in the project tree in the left column.

From what I understand, the wave port defines an electric field between two conductors at the port location in the model. You need to tell HFSS where the voltage potential is at the port. In other words, which conductor has a positive potential, and which conductor is used as the ground reference.

Its hard to tell from your image, but I don't see any ground plane, or any ground conductors that can be used as a common reference or ground between ports.

You might need to add a ground plane under your model structure (or around the structure) and define the plane as a reference in the wave port properties.