Confusion about SSH and backup to secure ftp server

I have big security concern which is about using classic ftp, service, so I have about 50 freepbx diffrent versions and I am trying to get the certificate to work. The thought is getting all 50 freepbx servers to do backup in the same way as ftp.

I Create my certificate using puttygen application, and put the files the proper places, but cannot get pass “not applying a password” and that is a mix between the web part and the system part.

The error I get is [EMPTY] password or null value missing

From the OS
[[email protected] ~]# ssh -i /var/www/html/admin/images/freepbxprivatekey.ppk [email protected]
Enter passphrase for key ‘/var/www/html/admin/images/freepbxprivatekey.ppk’:
[email protected]’s password:
Permission denied (publickey).

From the webpage I cannot set a password.

So some how I am supposed to get the private key into the OS and away from the OS/Asterisk user and I really want to keep the privatekey - private to the asterisk user which have file/folder access on the server.
But because I cannot supply a password the system newer gets to read the public key, or that is at least my understanding???

The documentation for setting this up newer goes into a systemadministrators point of view, where to “consume the public key” and where to put the private key file so that it is not in a html part of the system.

I am using 14.0.14 backup and restore module, but also see the same problem on older versions

Can any help lift the confusion about this??

Personal opinion, but why not SSH backups and store the public key at storage destination?