[pure-ftpd] VPN issues

Hello,

I have been using pure-ftpd for years without any problem. Thank you for 
all your efforts.

Lately, I wanted to install it on my home server which is behind a 
pfSense router. All the devices and the server on LAN reach out to the 
Internet through VPN client installed on pfSense. This creates problem 
with pure-ftpd which I have no idea how to solve.

Here is the client communication with pure-ftpd:

Warning: Allowing fallback to plaintext FTP is insecure. You should use 
explicit FTP over TLS.
Warning: Selected port (2100) is not the default port (21) of the 
selected protocol.
Status: Resolving address of ftp.burasidir.com
Status: Connecting to aaa.bbb.ccc.ddd
Warning: The entered address does not resolve to an IPv6 address.
Status: Connected, waiting for welcome message...
Reply: 220---------- Welcome to Pure-FTPd [privsep] [TLS] ----------
Reply: 220-You are user number 1 of 5 allowed.
Reply: 220-Local time is now 08:26. Server port: 2100.
Reply: 220-This is a private system - No anonymous login
Reply: 220 You will be disconnected after 15 minutes of inactivity.
Command: CLNT https://ftptest.net on behalf of 45.87.212.180
Reply: 530 You aren't logged in
Command: AUTH TLS
Reply: 500 This security scheme is not implemented
Warning: Server refused AUTH TLS, trying deprecated AUTH SSL fallback.
Command: AUTH SSL
Reply: 500 This security scheme is not implemented
Warning: Server refused AUTH SSL, falling back to insecure plaintext FTP.
Command: USER sse450
Reply: 331 User sse450 OK. Password required
Command: PASS **********
Reply: 230 OK. Current directory is /
Command: SYST
Reply: 215 UNIX Type: L8
Command: FEAT
Reply: 211-Extensions supported:
Reply: UTF8
Reply: EPRT
Reply: IDLE
Reply: MDTM
Reply: SIZE
Reply: MFMT
Reply: REST STREAM
Reply: MLST 
type*;size*;sizd*;modify*;UNIX.mode*;UNIX.uid*;UNIX.gid*;unique*;
Reply: MLSD
Reply: PRET
Reply: AUTH TLS
Reply: PBSZ
Reply: PROT
Reply: TVFS
Reply: ESTA
Reply: PASV
Reply: EPSV
Error: Carriage return without line feed received

Public IP denoted by aaa.bbb.ccc.ddd is my external IP of the router. 
However, CLNT command uses VPN out address. This situation ends up in 
"directory listing" problem.

Any idea how to fix this?

Thank you.

Best wishes to all list members.