freeradius DNS issue

I have two DNS entry in /etc/resolve.conf and somehow today 10.10.0.10 DNS went down and result radius fail to authenticate clients, it was bizarre that 1 hour everything was down and as soon as 10.10.0.10 came back radius start working, I have check 10.10.0.11 is totally functional DNS but look like freeradius just doesn't like getting failover to second DNS, is there any timeout or better solution of this issue? # cat /etc/resolv.conf nameserver 10.10.0.10 nameserver 10.10.0.11