Check your connection information (ftp server address, login, password). Pay close attention to the characters that resemble each other, for example, ' I', 'l' and ' 1 ' (capital I, lowercase L and the number one) or ' 0 ' and ' O' (zero and capital O) when typing your password.

- Check that you do not have a firewall configured in an overly secure fashion in order to allow access to your FTP storage.

- Check that you have correctly activated the "Passive" mode in your FTP transfer.

- Check that you have correctly sent your files to the directory "site".