500 Error reading 'isEmpty' on type com.nationalgeographic.componentry.sling.model.promo.BetaRelatedContentListPromo

Error reading 'isEmpty' on type com.nationalgeographic.componentry.sling.model.promo.BetaRelatedContentListPromo

Cannot serve request to /content/adventure/en_US/features/response-to-ski-towns-suicide-story.html on this server