FTPs (TLS) causing the connection to throw connection error (Pure-FTPd) - ssl

Question

Error: I won't open a connection to 127.0.0.1 (only to 172.20.0.1) (code=500)
My docker file is as below, I have tried passive ports range too but not sure about --expose here, I am able to connect at first through my code but at a second attempt or reusing it is throwing the above error.
I understand it has something with the passive mode but I have the configuration but not sure what is missing, please help.
version: '3'
services:
ftpd_server:
image: stilliard/pure-ftpd
container_name: pure-ftpd
privileged: true
ports:
- "21:21"
- "30000-30099:30000-30099"
volumes: # remember to replace /folder_on_disk/ with the path to where you want to store the files on the host machine
#- "/tmp/test/data:/home/username/"
#- "/tmp/test/passwd:/etc/pure-ftpd/passwd"
- "/upload:/home/upload"
#- "./certs:/etc/ssl/private"
environment:
PUBLICHOST: "localhost"
FTP_USER_NAME: lktransfer
FTP_USER_PASS: lktransfer
FTP_USER_HOME: /home/upload/
#FTP_PASSIVE_PORTS: "30000-30009"
FTP_MAX_CLIENTS: 50
FTP_PASSIVE_PORTS: 30000:30099
FTP_MAX_CONNECTIONS: 50
ADDED_FLAGS: "--tls=1"
#ADDED_FLAGS: "--tls=2"
TLS_USE_DSAPRAM: "true"
TLS_CN: "localhost"
TLS_ORG: "Ellkay"
TLS_C: "IN"
restart: always