Exception in rendering!

Message: Cannot read property 'document_key' of null

TypeError: Cannot read property 'document_key' of null
    at Header.render (<anonymous>:61781:59)
    at ReactCompositeComponentWrapper._renderValidatedComponentWithoutOwnerOrContext (<anonymous>:128451:30)
    at ReactCompositeComponentWrapper._renderValidatedComponent (<anonymous>:128474:32)
    at ReactCompositeComponentWrapper.performInitialMount (<anonymous>:128014:30)
    at ReactCompositeComponentWrapper.mountComponent (<anonymous>:127910:21)
    at Object.mountComponent (<anonymous>:11070:35)
    at ReactCompositeComponentWrapper.performInitialMount (<anonymous>:128023:34)
    at ReactCompositeComponentWrapper.mountComponent (<anonymous>:127910:21)
    at Object.mountComponent (<anonymous>:11070:35)
    at ReactDOMComponent.mountChildren (<anonymous>:131423:44)