Secure FTP is VERY Slow

I just purchased the Advanced FTP certificate add-on for my Directory Opus 11 software because I need to connect to my ftp server via secure TLS. Prior to this I was using just the standard connection and everything was working really well and all of my directories loaded almost immediately. Now that I have started using the secure TLS connection to log-in, it is VERY slow to establish capabilities and read the directories. Previously, using the standard connection, it took maybe 1-2 seconds to read the folder and display the contents and now it takes well over a minute every single time I change to a new folder. Any idea why this is happening and how to fix it?

FYI - when I log in using FileZilla, everything loads and reads very quickly so I know it's not my server.