A. The Linux Kernel Routing Daemon (LKRD) is not running and should be started using its init script or systemd unit.

B. One of the routers in the routing table is not available which causes the automatic router failure detection mechanism (ARF-D) to wait for a timeout.

C. There may accidentally be more than one default router in which case a default router election has to be done on the network in order to choose one router as the default.

D. The local routing information may be corrupted and must be re-validated using a routing protocol.

E. DNS resolution may not be working as route by default tries to resolve names of routers and destinations and may run into a timeout.