Namespace Router Shard gets error unable to find namespaces for router: User "system:openshift-router" cannot list all namespaces in the cluster

Issue

• When I configured Router Shards, the routing doesn't work.
• I checked router logs and found following message.

# oc logs router-2-8uuql
...
 E0116 09:55:49.535424       1 controller.go:75] unable to find namespaces for router: User "system:openshift-router" cannot list all namespaces in the cluster

• I got this error one of my cluster, but other clusters didn't. Why other clusters doesn't get it.