1. Open up Firefox and click on Tools > FireFTP

2. Click on the "Main" tab. Set up your FTP connection as usual.

Account Name: Whatever you want to call it to identify the Account
Host: yourdomain.com ("yourdomain.com is your actual domain)
User: your cPanel username
Password: Your cPanel Password

3. Next, click on the Connection tab. The defaults are OK here. Slect the "security" dropdown and select "Auth TLS"


When you connect, you will see a welcome message from the FTP server in the log that shows at the bottom of FireFTP

It will look like this:

 220---------- Welcome to Pure-FTPd [TLS] ----------
 220-You are user number 1 of 50 allowed.
 220-Local time is now 00:53. Server port: 21.
 220-This is a private system - No anonymous login
 220-IPv6 connections are also welcome on this server.
 220 You will be disconnected after 15 minutes of inactivity.
 AUTH TLS
 234 AUTH TLS OK.
 PBSZ 0
 200 PBSZ=0
 USER cPanel-username
 331 User b1419 OK. Password required
 PASS (password not shown)

 

Congratulations, you have successfully connected to the FTP server using FTPS over TLS!

 

NOTE: Some versions of FireFTP seem to have problems with this method. In those versions that you cannot connect via TLS there should be an "SFTP" option. Choosing that should work for you if TLS is not working.

If you must have TLS try another client like WinSCP.