Getting an ftp connection error on a plesk server:

15:04:41 Status: Resolving address of 66.226.xx.xx
15:04:41 Status: Connecting to 66.226.72.xx.xx
15:04:41 Status: Connection established, waiting for welcome message...
15:04:48 Status: Initializing TLS...
15:04:50 Status: Verifying certificate...
15:04:53 Status: TLS connection established.
15:04:59 Status: Connected
15:04:59 Status: Retrieving directory listing...
15:05:02 Command: PWD
15:05:02 Response: 257 "/" is the current directory
15:05:02 Command: TYPE I
15:05:02 Response: 200 Type set to I
15:05:02 Command: PASV
15:05:02 Response: 227 Entering Passive Mode (66,226,xx,xx1,46,242).
15:05:02 Command: MLSD
15:05:02 Error: The data connection could not be established: ECONNREFUSED - Connection refused by server
15:05:21 Error: Connection timed out after 20 seconds of inactivity
15:05:21 Error: Failed to retrieve directory listing
15:05:21 Status: Disconnected from server 

Edit your configuration file and comment out MasqueradeAddress:

# nano /etc/proftpd.conf

#MasqueradeAddress 66.226.xx.xx

Restart xinetd

# service xinetd restart