Does Nomorobo Max need to be open in the background? Follow Nope! Nomorobo Max does not need to be open in the background in order to work properly. Related articles Why does Nomorobo Max recommend notifications and contacts access? My phone carrier doesn't support Nomorobo Max How does Nomorobo Max Call Screening work? How to Toggle SMS Filter & SMS Spam Reporting Is there a friends & family plan?