I am running Debian Buster on my server, and after reading these instructions I have added the following lines to my vsftpd.conf:
rsa_cert_file=/etc/letsencrypt/live/***.com/fullchain.pem rsa_private_key_file=/etc/letsencrypt/live/***.com/privkey.pem ssl_enable=YES ssl_ciphers=HIGH 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
After restarting vsftpd, when I try to access the server from FileZilla using explicit FTP over TLS, I see a CONNECT in /var/log/vsftpd.log, but it is unable to proceed with the AUTH TLS (connection times out).
If I try to access it using plain FTP, it does reject the login.
The SSL certificate works fine with https.
Any suggestions for things to check?