MAC OS error "no matching host key type found. Their offer: ssh-dss "

edit file /etc/ssh/ssh_config

1. Scroll down until you see this line: 

         #   MACs hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160

2.  Delete the pound sign, which will un-comment that line and make it active.

3. Now scroll down to the bottom of the document and add this line:  
        HostkeyAlgorithms ssh-dss