XBee S2C Coordinator not forming the same network after power loose

Hello, i have an issue what i can’t not understand. I have some of XBee S2C modules in one Digi mesh network. This is encrypted network with ZigBee trust center link key, fixed Extended PAN ID on fixed (one) ZigBee channel. All devices - the routers (with one coordinator). All works fine, but sometime the power cutoff. After power on again, the coordinator not forming the same network, but form another network, and, of course, not communicate with devices in previous network. If i do the hardware reset of coordinator by button - all works again. How to set the coordinator to form the same network after the power loose? What parameters must be set in XCTU to achive this goal?