How to get a restarted Coordinator to communicate with a running Router?

When the watchdog timer expires on an XBee Series 2B Coordinator (Firmware 21A7) it causes the Coordinator to restart. After the restart the Router (Firmware version 23A7) is no longer available for communication. I have the NJ parameter on the Coordinator set to 0xFF and the JV parameter on the Router enabled. I’m not sure if the problem is that the Router is no longer actively looking for the Coordinator or that the Coordinator won’t allow the Router to join the restarted network (or maybe something completely different from this). What else do I have to set or do to automatically re-establish communication between these devices when this happens?

First off, what watch dog is being reset on the Coordinator? The only watch dog timers on the coordinator that would cause a reset would be the result of a hardware connection issue or a voltage issues.

Next, your JV and NW parameters on the router should allow it to reset once the coordinator is no longer found on the network for 3 times the NW parameter.