OperationTimeoutException when reading or writing


I have the following environment:
Couchbase version: 3.0.1 community edition with 1 node couchbase server
and tomcat with webservice that use couchbase client, when I reading or writing
from couchbase, from some time, I’m getting the following error:
Caused by: net.spy.memcached.internal.CheckedOperationTimeoutException:
Timed out waiting for operation - failing node:
at net.spy.memcached.internal.OperationFuture.get(OperationFuture.java:167)
at net.spy.memcached.internal.OperationFuture.get(OperationFuture.java:140)
… 67 more

Thank you very much