Unable to connect to a server via FTP: 421 Service not available, remote server has closed connection

Symptoms

• Connection to a server via FTP fails with the following error message:

  CONFIG_TEXT: 421 Service not available, remote server has closed connection

  OR

  CONFIG_TEXT: Status: Connecting to 203.0.113.2:21...
  Status: Connection established, waiting for welcome message...
  Error: Could not connect to server

• The following error can be found in a system logfile (/var/log/messages for CentOS/RHEL, /var/log/syslog for Debian/Ubuntu) (connection via SSH is required):

  CONFIG_TEXT: proftpd[11783]: Fatal: ScoreboardFile: : unable to use '/var/run/proftpd/scoreboard': No such file or directory on line 45 of '/etc/proftpd.conf'
  xinetd[2312]: EXIT: ftp status=1 pid=11783 duration=0(sec)

  OR

  CONFIG_TEXT: error: cannot read configuration path '/etc/proftpd.d': Not a directory
  fatal: Include: error including '/etc/proftpd.d/*.conf': Invalid argument on line 95 of '/etc/proftpd.conf'

• The directory /var/run/proftpd/ is missing:

  # ls -l /var/run/proftpd/
  ls: cannot access /var/run/proftpd/: No such file or directory

Cause

This is a Plesk bug with ID PPPM-3332, which is planned to be fixed in future product updates.

Resolution

1. Connect to a Plesk server via SSH.

2. Create the missing directory:

   # mkdir /var/run/proftpd/

3. Restart the xinetd service:

   # service xinetd restart