EC21-connect FTPS (implicit) server error 522 data connections must be encrypted

Hello I have an EC21, I cannot login to the ftps implicit server I created on centos, the error appears “522 data connections must be encrypted”

CONNECT: Client “xxx”
response: Client “xxx”, “220 (vsFTPd 3.0.2)”
command: Client “xxx”, "USER "
response: Client “xxx”, “331 Please specify the password.”
command: Client “xxx”, "PASS "
OK LOGIN: Client “xxx”
response: Client “xxx”, “230 Login successful.”
command: Client “xxx”, “SYST”
response: Client “xxx”, “215 UNIX Type: L8”
command: Client “xxx”, “CWD /”
response: Client “xxx”, “250 Directory successfully changed.”
command: Client “xxx”, “TYPE A”
response: Client “xxx”, “200 Switching to ASCII mode.”
command: Client “xxx”, “PASV”
response: Client “xxx”, “227 Entering Passive Mode (xxx).”
command: Client “xxx”, “LIST .”
Client “xxx”, “522 Data connections must be encrypted.”

configure my server:

pasv_enable=YES
pasv_address=3.0.175.207
pasv_min_port=60001
pasv_max_port=60010
force_dot_files=YES
use_localtime=YES
allow_writeable_chroot=YES
listen=YES
listen_ipv6=NO
pasv_addr_resolve=NO

rsa_cert_file=/var/key/vsftpd.crt
rsa_private_key_file=/var/key/vsftpd.key
ssl_enable=YES
allow_anon_ssl=NO
force_local_data_ssl=YES
force_local_logins_ssl=YES
ssl_tlsv1=YES
ssl_sslv2=NO
ssl_sslv3=NO
require_ssl_reuse=NO
ssl_ciphers=HIGH
user_sub_token=$USER
implicit_ssl=YES
listen_port=990

I have tried using winscp to the server successfully and the file is upload, download to the server.
And I also try sim module 7600ce-t that just login to the server, cannot perform other operations, often reports time out.

Pls help me. Thanks

Hello, thanks for your question
Can describe your application scenarios and usage more clearly, if possible, please grab the relevant exception log and send it to support@quectel.com, thank you.