Issue Connection to server using Remote-FTP atom package and Private Keys

I'm trying to connect to my server using the atom package "Remote-FTP" and using a private key.

I have the SSH keys set up on my server and can connect successfully using putty.

The private key is saved in my project folder and I have an existing .ftpconfig file (without a private key) that connects successfully when I replace the information inside the file.

The Key has been converted to the necessary ssh format and I have no passphrase at the moment. I have also gave the full path of the private key file

Here is my .ftpconfig file -

{"protocol": "sftp","host": "user@server","port": 22,"user": "","pass": "","promptForPass": false,"remote": "","local": "","agent": "","privatekey": "putty_private_key_sbappsupconvrted.ppk","passphrase": "","hosthash": "","ignorehost": true,"connTimeout": 10000,"keepalive": 10000,"keyboardInteractive": true,"watch": [],"watchTimeout": 500}

The error code I am receiving is:

REMOTE FTP: Connection...

REMOTE FTP: Connection failed Error: getaddrinfo EAI_FAIL user@server: 22

REMOTE FTP: Connection closed

I have also given the full path of the private key file

C:\Users\user\.atom\server\putty_private_key_sbappsupconvrted.ppk

and I get this error

Could not parse .ftpconfig Unexpected token U in JSON at position 219

Any help would be greatly appreciated