sometimes, in addition to the Centos-Webpanel Wiki about using Passv mode, there is another reason for this issue that has nothing to do with firewalls.
for example,
A. If you use Filezilla, then check the following...
Filezilla>File Menu>Site Manager>My Sites (select your saved site)
Then go to over to the right-hand side of Filezilla window and look at tabs (General, Advanced, Transfer settings, Charset) and click "Advanced" tab
Ensure that under "Default Remote Directory" you have at least given a directory...I use "/" (without "").
B. If using WinSCP, then do the following...
Goto Sessions>Sites>Site Manager>Edit Site> Advanced>Directories>Remote Directory, and ensure that "/" (without "") is set as your remote directory.
This fixes the problem for me in both of the above ftp clients.