MySQL SSH - Provided key is ivalid

What is the format for the SSH Private Key for the MySQL SSH connector?  I have verified that I can connect using this user and key in Putty, but I'm getting "Provided key is invalid" in the connector.  There shouldn't be any need to whitelist DOMO's ip addresses as the ssh server's ssh port is open to all.  The database server has the ssh server's internal IP whitelisted.