There was a problem with VSFTPD on Ubuntu 18.04. It was not so long ago I used it and he worked stably and here it gives it an error “500 Oops: VSFTPD: refusing to run with writable root inside chroot ()” and it is when connected and not authorization.
Log – empty.
You can get around the check by putting the flag:
echo 'allow_writeable_chroot = yes' & gt; & gt; /etc/vsftpd/vsftpd.conf.
and restart the service
SystemCTL Restart VSFTPD