So /api is a routing folder that only exists virtually in the php framework - it’s not physically present on the filesystem.
Can you check database connectivity? If UFW is blocking that it could be the issue. The login not working also suggests this issue. Also ensure there are tables in the dreamfactory database.
The only other thing I could think of that would be port/firewall related is the php process itself, but I’ve never run into that unless I was using nginx.