The following exception can be found from the logs. The "Excluded External Referrer Prefixes" list is empty.

2005-02-17 10:35:15,019 ERROR [atlassian.confluence.links.ReferralTaskQueue] Unable to add referrer http://xxx.yyy.zzz/abc/def - No persister for: com.atlassian.confluence.pages.Page$$EnhancerByCGLIB$$42005a61
net.sf.hibernate.MappingException: No persister for: com.atlassian.confluence.pages.Page$$EnhancerByCGLIB$$42005a61
at net.sf.hibernate.impl.SessionFactoryImpl.getPersister(SessionFactoryImpl.java:347)
at net.sf.hibernate.impl.SessionImpl.getClassPersister(SessionImpl.java:2690)
at net.sf.hibernate.impl.SessionImpl.doLoadByClass(SessionImpl.java:1988)
at net.sf.hibernate.impl.SessionImpl.load(SessionImpl.java:1920)
at com.atlassian.confluence.links.ReferralTask.execute(ReferralTask.java:27)
at com.atlassian.confluence.links.ReferralTaskQueue.flush(ReferralTaskQueue.java:74)
at sun.reflect.GeneratedMethodAccessor263.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at org.springframework.aop.framework.AopProxyUtils.invokeJoinpointUsingReflection(AopProxyUtils.java:61)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:149)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:116)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:56)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:138)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:152)
at $Proxy30.flush(Unknown Source)
at com.atlassian.confluence.event.jobs.ReferralQueueFlushJob.doExecute(ReferralQueueFlushJob.java:26)
at bucket.event.jobs.AbstractJob.executeInternal(AbstractJob.java:85)
at org.springframework.scheduling.quartz.QuartzJobBean.execute(QuartzJobBean.java:66)
at org.quartz.core.JobRunShell.run(JobRunShell.java:191)
at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:516)