VSFTPD Error: GnuTLS error -9: A TLS packet with unexpected length was received.
I was tasked with configuring VSFTPD to allow SFTP or FTPES (FTP over explicit TLS/SSL) tonight for a client. The configuration already had regular FTP working which I verified using FileZilla as an FTP client. I was able to login and transfer files in both directions to and from the server. Next I verified that SFTP worked without issue and I was able to also transfer files in both directions using SFTP. For FTPES I had to make some changes and once I did make the changes I was still getting an error when attempting to do a directory listing using FileZilla. Below I describe the initial changes I made to vsftpd.conf, the errors I received attempting to connect with FTPES, and the way I resolved the problem.