When you create a service,
if you set destination as a hostname (not ip), please check on ferrumgate machine to ping $hostnamethatyouentered, (check also if ipv4 is resolved)
If you enter an ip as destination, please check ping $ipthatyouentered
Then on the client, after connected to ferrumgate successfuly
please check ping $servicename
if both of them works, please check Policy/Authorization rule
On ferrumgate machine I can ping hostname and resolve with an IPv4
On client when I set any services I can ping even and the Policy/Authorization rule is OK because when I change the hostname to IP on service I can connect.