Looking for a down payment loan for a apartment building

I intend to purchase a 5-million-dollar apartment building in Florida. I received a 3.5 million loan approval from a bank. I require a second loan of 1.5 million dollars. Could someone please tell me how to secure a down payment loan? When I called private money and hard money lenders, they stated they couldn't give me a second loan on the property because I already had a 3.5 million loan. Appreciate any input. Thanks in advance.