You can easily fix this error by going into the site manager and adjusting your connection details to use plain FTP. Follow these steps to fix the problem:

1. In FileZilla, click on ?File? menu and choose ?Site Manager?
2. Add the site or server you want to connect to if it?s not already in site manager.
   1. Add hostname
   2. change encryption to ?only use plain FTP?
   3. Change logon type "Normal"
   4. Enter username/password.
   5. Ok/Connect to continue

If the problem still persists, please disable your firewall then try once more! If it still fails,  here is what you need to do:

• Open Filezilla, go to Edit -> Settings
• Click on Connection -> FTP: Choose Active
• Click on Connection -> FTP -> Active Mode: Select "Ask your operating system for the external IP address"
• Click on Connection -> FTP -> Passive Mode: Choose Fall Back to Active Mode
• Press OK.

Try connecting to your FTP again!