Check for the existence of the file
sshd_config (/etc/ssh/sshd_config).
Before editing the file check that path settings for sftp-server
$ locate sftp-server
/usr/libexec/openssh/sftp-server
Check for the existence of following line in sshd_config
Subsystem sftp /usr/libexec/openssh/sftp-server
(more…)