It happens because you don’t have images/listing-images/rent path existing in your filesystem.
If you want to create the whole path – just pass the 3rd argument as a true:
mkdir('images/listing-images/rent/'.$insertID, 0777, true);
There is also a chance you’re in a wrong directory currently. If this is the case – you need to change the current dir with chdir() or specify the full path.