Unable to create a backup in Confluence Cloud

2015-10-26 22:19:12.423243500 2015-10-26 22:19:12,418 INFO [ajp-bio-127.0.0.101-8009-exec-2] [ondemand.backupmanager.rest.RootResource] runBackup Starting OnDemand backup
2015-10-26 22:19:12.428459500 2015-10-26 22:19:12,426 INFO [ajp-bio-127.0.0.101-8009-exec-2] [atlassian.ondemand.backupmanager.BackupProcessManagerImpl] startBackup Generated task id = 77fb242b-75c9-48c0-95e4-d9bc60c5c19c
2015-10-26 22:19:12.434427500 2015-10-26 22:19:12,432 INFO [ajp-bio-127.0.0.101-8009-exec-2] [ondemand.backupmanager.rest.RootResource] runBackup OnDemand backup finished
2015-10-26 22:19:12.435883500 2015-10-26 22:19:12,435 INFO [Long running task: OnDemandBackup] [ondemand.backupmanager.confluence.OnDemandExporter] doInTransaction Preparing for backup
2015-10-26 22:19:12.501444500 2015-10-26 22:19:12,499 INFO [Long running task: OnDemandBackup] [atlassian.confluence.upgrade.AbstractUpgradeManager] getExportBuildNumber Backward compatibility for export: Checking...
2015-10-26 22:19:12.502071500 2015-10-26 22:19:12,501 INFO [Long running task: OnDemandBackup] [atlassian.confluence.upgrade.AbstractUpgradeManager] getExportBuildNumber Build number 6189: "Upgrade to build number: 6189" - Ok
2015-10-26 22:19:12.503344500 2015-10-26 22:19:12,502 INFO [Long running task: OnDemandBackup] [atlassian.confluence.upgrade.AbstractUpgradeManager] getExportBuildNumber Build number 6180: "Adds a multi-column index to content table that speeds up many common queries." - Ok
2015-10-26 22:19:12.503842500 2015-10-26 22:19:12,503 INFO [Long running task: OnDemandBackup] [atlassian.confluence.upgrade.AbstractUpgradeManager] getExportBuildNumber Build number 6175: "Upgrade to build number: 6175" - Ok
2015-10-26 22:19:12.504357500 2015-10-26 22:19:12,503 INFO [Long running task: OnDemandBackup] [atlassian.confluence.upgrade.AbstractUpgradeManager] getExportBuildNumber Build number 6169: "Upgrade to build number: 6169" - Not Ok
2015-10-26 22:19:12.504865500 2015-10-26 22:19:12,504 INFO [Long running task: OnDemandBackup] [atlassian.confluence.upgrade.AbstractUpgradeManager] getExportBuildNumber Backward compatibility for export: "Upgrade to build number: 6169" prevents compatibility before 6169
2015-10-26 22:19:12.778433500 2015-10-26 22:19:12,777 ERROR [Long running task: OnDemandBackup] [ondemand.backupmanager.rest.OnDemandBackupTask] errorDuringExecution Failure during task executing. Task's service: com.atlassian.ondemand.backupmanager.confluence.OnDemandExporter@1ce5510
2015-10-26 22:19:12.778436500  -- referer: https://milkcoffee.atlassian.net/wiki/plugins/servlet/ondemandbackupmanager/admin | url: /wiki/rest/obm/1.0/runbackup | userName: janice
2015-10-26 22:19:12.778436500 org.springframework.transaction.UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only
2015-10-26 22:19:12.778452500 	at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:695)
2015-10-26 22:19:12.778453500 	at sun.reflect.GeneratedMethodAccessor40.invoke(Unknown Source)
2015-10-26 22:19:12.778453500 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
2015-10-26 22:19:12.778455500 	at java.lang.reflect.Method.invoke(Method.java:483)
2015-10-26 22:19:12.778456500 	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
2015-10-26 22:19:12.778456500 	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:198)
2015-10-26 22:19:12.778460500 	at com.sun.proxy.$Proxy16.commit(Unknown Source)
2015-10-26 22:19:12.778460500 	at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:140)
2015-10-26 22:19:12.778461500 	at com.atlassian.sal.spring.component.SpringHostContextAccessor.doInTransaction(SpringHostContextAccessor.java:68)
2015-10-26 22:19:12.778462500 	at sun.reflect.GeneratedMethodAccessor208.invoke(Unknown Source)
2015-10-26 22:19:12.778463500 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
2015-10-26 22:19:12.778464500 	at java.lang.reflect.Method.invoke(Method.java:483)
2015-10-26 22:19:12.778464500 	at com.atlassian.plugin.util.ContextClassLoaderSettingInvocationHandler.invoke(ContextClassLoaderSettingInvocationHandler.java:26)
2015-10-26 22:19:12.778465500 	at com.sun.proxy.$Proxy243.doInTransaction(Unknown Source)
2015-10-26 22:19:12.778466500 	at sun.reflect.GeneratedMethodAccessor208.invoke(Unknown Source)
2015-10-26 22:19:12.778467500 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
2015-10-26 22:19:12.778467500 	at java.lang.reflect.Method.invoke(Method.java:483)
2015-10-26 22:19:12.778468500 	at com.atlassian.plugin.osgi.bridge.external.HostComponentFactoryBean$DynamicServiceInvocationHandler.invoke(HostComponentFactoryBean.java:136)
2015-10-26 22:19:12.778471500 	at com.sun.proxy.$Proxy243.doInTransaction(Unknown Source)
2015-10-26 22:19:12.778471500 	at com.atlassian.sal.core.transaction.HostContextTransactionTemplate.execute(HostContextTransactionTemplate.java:18)
2015-10-26 22:19:12.778472500 	at sun.reflect.GeneratedMethodAccessor238.invoke(Unknown Source)
2015-10-26 22:19:12.778472500 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
2015-10-26 22:19:12.778474500 	at java.lang.reflect.Method.invoke(Method.java:483)
2015-10-26 22:19:12.778474500 	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302)
2015-10-26 22:19:12.778475500 	at org.eclipse.gemini.blueprint.service.importer.support.internal.aop.ServiceInvoker.doInvoke(ServiceInvoker.java:56)
2015-10-26 22:19:12.778475500 	at org.eclipse.gemini.blueprint.service.importer.support.internal.aop.ServiceInvoker.invoke(ServiceInvoker.java:60)
2015-10-26 22:19:12.778477500 	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
2015-10-26 22:19:12.778478500 	at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:133)
2015-10-26 22:19:12.778478500 	at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:121)
2015-10-26 22:19:12.778482500 	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
2015-10-26 22:19:12.778482500 	at org.eclipse.gemini.blueprint.service.util.internal.aop.ServiceTCCLInterceptor.invokeUnprivileged(ServiceTCCLInterceptor.java:70)
2015-10-26 22:19:12.778483500 	at org.eclipse.gemini.blueprint.service.util.internal.aop.ServiceTCCLInterceptor.invoke(ServiceTCCLInterceptor.java:53)
2015-10-26 22:19:12.778485500 	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
2015-10-26 22:19:12.778486500 	at org.eclipse.gemini.blueprint.service.importer.support.LocalBundleContextAdvice.invoke(LocalBundleContextAdvice.java:57)
2015-10-26 22:19:12.778486500 	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
2015-10-26 22:19:12.778490500 	at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:133)
2015-10-26 22:19:12.778491500 	at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:121)
2015-10-26 22:19:12.778495500 	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
2015-10-26 22:19:12.778496500 	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
2015-10-26 22:19:12.778496500 	at com.sun.proxy.$Proxy1893.execute(Unknown Source)
2015-10-26 22:19:12.778497500 	at com.atlassian.ondemand.backupmanager.confluence.OnDemandExporter.backup(OnDemandExporter.java:94)
2015-10-26 22:19:12.778499500 	at com.atlassian.ondemand.backupmanager.rest.OnDemandBackupTask.run(OnDemandBackupTask.java:84)
2015-10-26 22:19:12.778499500 	at com.atlassian.ondemand.backupmanager.longrunning.ManagedTask.run(ManagedTask.java:35)
2015-10-26 22:19:12.778500500 	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
2015-10-26 22:19:12.778500500 	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
2015-10-26 22:19:12.778502500 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
2015-10-26 22:19:12.778502500 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
2015-10-26 22:19:12.778503500 	at java.lang.Thread.run(Thread.java:745)