this normally happens with filezilla. we had a post from 2010 about this here.
so this is an update, first check if you using the correct login info, then if still not working do:
- Open Filezilla and open the settings (under the Edit menu)
- Under “Connection” select “FTP”
- The section at the top is called Transfer Mode. Within that, choose “Passive Mode”
- Click OK. You should now be able to connect.