Plesk FTP not working but SFTP and Shell is working

I am facing a strange problem. The FTP on my Plesk VPS is not working. Whenever I try to connect, FileZilla FTP client says:

Status: Resolving address of xxxxxxxxxxxxx.com
Status: Connecting to xxx.xxx.xxx.xxx:21...
Status: Connection established, waiting for welcome message...
Error: Could not connect to server

So, it's not even going to the step of asking username/password. So, it's something else.

---

The SFTP on port 22 is working fine. Also, I can successfully do shell access and run commands.

But, I NEED FTP access too on port 21. I have searched everywhere but can not find any setting to enable it. This is the Plesk version info:

Parallels Plesk Panel version 9.5.2
Operating system Linux 2.6.26.8-57.fc8
CPU GenuineIntel, Intel(R) Pentium(R) 4 CPU 3.00GHz

Any help is appreciated.

[EDIT]:

The firewall is not blocking it. I have checked it on server and there are absolutely no blocking rule. Firewall states:

All incoming/outgoing connections are accepted on FTP

And on client-side (my PC), I can connect to other FTP servers so this is not an issue in my PC's firewall. Moreover, I can not even connect to the FTP from online FTP clients like net2ftp.

From serverfault shamittomar

• Maybe your VPS provider doesn't want you to use FTP (it's not very secure after all...)? Did you check their documentation and/or ask their support people about this?

  shamittomar : I have got the root access and everything. I can enable that myself. Just want to know how to do that.
  From JanC

• I would check if FTP server is running at all. It could be also blocking rule on firewall
  --
  Regards,
  Robert

  shamittomar : Firewall is not an issue. See my updated question. And **how do I check if FTP server is running or not?** What command should I issue on shell to check this. Please elaborate.

  JanC : You can check the output of `netstat -tlp` run as root.
  From Robert