First, try setting your FTP client to active mode, and disable passive mode. If this does not work, set the client back to passive, and connect to one of the following servers with your VPN client:
Otherwise, using sFTP may work successfully, which connects to your FTP server securely via SSH.
If you're using a connectivity method other than our application, you can also try manually specifying an IP for your gateway address in your connection, which may help. You can obtain an IP for any given gateway by pinging it via command prompt/terminal.
If the above steps do not work, please try disconnecting the VPN and using our SOCKS5 proxy in your FTP client:
The proxy requires authentication, and uses a special username and password. Instructions for obtaining the username and password can be found here.
(Please note: The proxy does not encrypt internet traffic, it only masks your IP address. However, if you operate the VPN and proxy together, they may destabilize your connection).