Apple - Connect to FTP server in Finder not working

I figured out the problem. I sniffed the traffic from my computer to the FTP server and saw traffic go through when I connected as a guest. I did not, however, see any traffic when I connected as myself. No traffic whatsoever was going through. On a whim, I tried a blank password and saw traffic going through! After changing my password on the FTP server I was successfully able to connect with Finder. It apparently had something to do with my password??? I played around to see what the exact problem was with my password and, at the risk of revealing too much information about my security credentials, found that any password with an '@' symbol in it caused Finder to immediately display that error and not even try to send any traffic to the FTP server.

Use username+domain instead username@domain

Example:

ftp://username+domain.com:[email protected]