FortiDNS Server London unreachable

Hello,

since last Saturday, the Fortiguard DNS Server located in London (IP:80.85.69.54) does not resolve DNS queries for our environment anymore. However it seems not to be a local problem of our Fortiguards, as even DNS queries through Internet lookups (https://dnslookup.online) don't get resolved when they are forwarded to this London FortiDns Server.

Is this a planned outage, has this server been retired or just its IP being changed ?

Best Regards

Klaus