Lots of extra.calendar3.license.LicenseAccessor ERRORs in logs

2014-09-06 05:28:54.202563500 2014-09-06 05:28:54,199 ERROR [TP-Processor6] [extra.calendar3.license.LicenseAccessor] isOnDemandLicense There seems to be a problem with the Confluence license...
2014-09-06 05:28:54.202565500  -- url: /wiki/display/intranet/My+Page | userName: sysadmin | referer: https://mydomain.atlassian.net/wiki/display/TEST/Home
2014-09-06 05:28:54.202566500 com.atlassian.license.LicenseException: License string or hash are null.
2014-09-06 05:28:54.202566500 	at com.atlassian.license.LicensePair.<init>(LicensePair.java:73)
2014-09-06 05:28:54.202577500 	at com.atlassian.confluence.extra.calendar3.license.LicenseAccessor.getProductLicenseString(LicenseAccessor.java:271)
2014-09-06 05:28:54.202578500 	at com.atlassian.confluence.extra.calendar3.license.LicenseAccessor.isOnDemandLicense(LicenseAccessor.java:220)
2014-09-06 05:28:54.202578500 	at com.atlassian.confluence.extra.calendar3.condition.OnDemandWebItemCondition.shouldDisplay(OnDemandWebItemCondition.java:19)
2014-09-06 05:28:54.202580500 	at com.atlassian.confluence.extra.calendar3.condition.CalendarCondition.shouldDisplay(CalendarCondition.java:21)
2014-09-06 05:28:54.202581500 	at com.atlassian.confluence.plugin.descriptor.web.conditions.BaseConfluenceCondition.shouldDisplay(BaseConfluenceCondition.java:38)
2014-09-06 05:28:54.202584500 	at com.atlassian.plugin.web.conditions.AndCompositeCondition.shouldDisplay(AndCompositeCondition.java:14)
2014-09-06 05:28:54.202585500 	at com.atlassian.plugin.web.conditions.AndCompositeCondition.shouldDisplay(AndCompositeCondition.java:14)
2014-09-06 05:28:54.202585500 	at com.atlassian.plugin.web.DefaultWebInterfaceManager.filterFragmentsByCondition(DefaultWebInterfaceManager.java:172)
2014-09-06 05:28:54.202587500 	at com.atlassian.plugin.web.DefaultWebInterfaceManager.getDisplayableItems(DefaultWebInterfaceManager.java:103)
2014-09-06 05:28:54.202588500 	at com.atlassian.confluence.plugin.descriptor.web.ConfluenceWebInterfaceManager.getDisplayableItems(ConfluenceWebInterfaceManager.java:88)
2014-09-06 05:28:54.202588500 	at sun.reflect.GeneratedMethodAccessor6383.invoke(Unknown Source)
2014-09-06 05:28:54.202590500 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)