After a short Internet connectivity issue, in an attempt to reconnect to FTP it will try using Active mode instead, which is not allowed on the server's side.

In this mode, FileZilla first establishes a connection with the FTP server using Passive mode. The incoming traffic to port 20/tcp(ftp-data) has to be allowed in order to establish the FTP data transfer while connecting via FTP in Active Mode.īy default, in FileZilla client > Site Manager > Transfer Settings > Transfer mode is set to Default. Port 20 is reported to be filtered on the server: On failed attempts to connect, the following error can be found in the /var/log/auth.log log file:ĬONFIG_TEXT: plesk proftpd: 0.0.0.0 (203.0.113.2) - mod_tls/2.7: unexpected OpenSSL error, disconnectingĪ combination of unstable Internet connection, blocked FTP active mode, and FileZilla's settings: PLESK_INFO: Error: The data connection could not be established: ECONNREFUSED - Connection refused by server. The following error is shown in FileZilla: An FTP connection to the Plesk server with the IP address 203.0.113.2 is dropped randomly when FileZilla client is used.

Filezilla port connections