No appearance type for dynamic categories?

Hi there

I was wondering if someone could help me or give some advice please.

Every time I try and add a dynamic category as a block there is no appearance type for it. See screenshot below:

I was wondering if anybody had come across this problem before and knew what to do. Is there anywhere I can download an appearance for this?

Thanks very much.

I was wondering if anybody had any ideas on this.

Is there a file missing somewhere hence why the the dropdown is empty. My theme is fairly standard.

Thanks very much