Ping loss to DNS looks like issue with your last mile connectivity and not Zima Radius.
You using Fibre or Wireless to connect last mile.
My connectivity with Optic Fibre . When i check Direct line Ping is Good. But when check client mode Ping is Loss
Suggest you to post on Mikrotik Site rather is Zima.
Even the ping is too high, which place you from?
But I am Configure My router in a Hotspot mode. that time client mode Ping is good.
Ping from client to same Google DNS 8.8.8.8 is good?
Do have i change something Configure my router for Zima Radius
Share your Mikrotik Config
I see that your Router is not configured optimally.
Suggest you to reset the router, reconfigure with basic setup one at a time with hotspot or pppoe and check and post result.
Also suggest to post the same in mikrotik forum.