About ssh-rsa 4096 hostkey

Hello, this is MinJi.

I was trying to access SFTP server using a script with the ssh-rsa 4096 hostkey. However, the access is denied. (The hostkey is from Server and Protocol Information Dialog session.)
Could you please check where in the script below is error?
Please refer that similar code using ssh-rsa 2048 hostkey was operated on other FTP server.

Host keys are used with SSH/SFTP. Not with FTP. If you are connecting to an SFTP server, you need to change ftp:// to sftp://.
And remove all of -passive -explicitssl -explicittls -implicit, as they have no effect with SFTP (and they even contradict one another).

As it seems that you can connect with WinSCP GUI, you can have it generate a code template for you: https://winscp.net/eng/docs/ui_generateurl#script

After I changed ftp to sftp in the script, the error has been resolved! Thank you, @martin!