Assistance in Configuring FTP Using CoreFTP

FTP encryption of some sort is, of course, highly recommended, but the best and latest standard is FTP over TLS, which is not only faster, but more secure than FTP over ssh.

My advice would be to use Pure-ftpd instead of CoreFTP on the server side. And for the client side—obviously—Filezilla.
I use CoreFTP all the time. Try setting it up manually. I use the IP address of my host rather than a URL. The only advanced settings I'm using are for the folders both local and remote. I'm using Port 2200 with SSH/SFTP. Your upload speed will only be as fast as your internet connection allows. And I appreciate that CoreFTP reminds me to backup my sites monthly. Hope that helps.