cant create unique districts?

[Vatten och Bröd]

I am trying to build the two special buildings for spain in the same district but it refuses to allow me to.

Can you only have one unique district per city..?

[Judicant]

You probably have an ageless building in the other slot, or the palace/city hall. These can’t be overbuilt.

[Luckiernut]

Yea either the other is the palace or ageless