In one aspect, there is provided a method for the management of Short Message SM delivery in a mobile communication system comprising an Overlaying, e.g. IP-based or CS fallback in Evolved Packet System based, SM delivery network accessed via a mobile or fixed Access Network AN which is transparent to the Overlaying SM Delivery procedure, said method comprising, in an embodiment: informing an AN entity capable of detecting User Equipment UE activity over said AN, of unsuccessful SM delivery attempt due to not reachable UE, upon detection of UE activity over said AN for said UE, said AN entity informing an entity in charge of requesting new SM delivery attempt when said UE is again reachable.