[atlas] Ping Fails (ns.ripe.net)

In reviewing My Probe stats, it appears that (ns.ripe.net) was once able to ping the server, but now it appears to be failing. All my other ping stats under My Probe show successful pings to other servers, but for some reason ns.ripe.net is failing. Does anybody have a suggestion of what might be going on, since ping is working to all the other servers. -Alby