About proxy mode, when all home servers are dead

Dear All, I have a FreeRADIUS 2.2.3 run in proxy mode to 2 home RADIUS servers in failover mode. The problem I face now is that when both home RADIUS servers are dead, FreeRADIUS will send a reject to NAS

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ERROR: Failed to find live home server for realm net-yan.com>>There was no response configured: rejecting request 2 When NAS receive a reject, it won't failover to another redundant RADIUS. Is there a way to configure FreeRADIUS such that it will not send another response back to NAS when all home RADIUS are dead?I have been studying the "do_not_respond" policy, but not sure how to use it in this case.. NAS --> primary: my FreeRADIUS --> Home RADIUS --> secondary: another RADIUS --> Home RADIUS

Thanks a lot! Regards,Leo