ping.nextdns.io doesn’t work in Optus Mobile

ping.nextdns.io is not working in Optus Mobile using Ultra Low Latency Mode.

It doesn’t show which server I am connected. 

Please see attached. ping.nextdns.io shows I am not connected but test.nextdns.io shows I am connected in Adelaide Server.

I am in Melbourne. Should my Server be Melbourne instead of Adelaide?

I am using mobile ios so i can run diag.