WinSCP hangs while listing directory

While connecting to any FTP server, WinSCP stops when retrieving directory listing with such an error:

Lost connection.

Timeout detected.
Could not retrieve directory listing
PORT command successful
Error listing directory '/obrazy'.

This is a new behaviour (previously everything was OK when connecting) and does not affect SFTP connections.

I found a solution:
Passive mode needs to be turned on in connection settings.

There was no such requirement in the past though.