Trouble with snapshot destination

I'm trying to set up some destinations for my snapshots to keep disk space on my production server low.

When trying to FTP to my home mac server, I'm getting this error when Testing the connection. (When testing SFTP, nothing happens)

ftp_connect failed.mysql_connect(): The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead

Is this a problem with my web server, or the receiving mac server?

I've been able to successfully FTP and SFTP to the mac server using Transmit