Why is FTX banned in US?

Could you elaborate on the reasons behind the ban of FTX in the United States? I've been hearing a lot of speculation but I'm looking for a concise and factual explanation. I'm curious about the specific regulatory concerns or violations that led to this decision. Was it due to issues with their business practices, lack of compliance with US laws, or something else entirely? Understanding the reasons behind this ban would help me gain a clearer perspective on the current regulatory landscape for cryptocurrencies in the US.