A core telecommunications-network device can receive a request associated with user equipment (UE) and transmit a third-party request on behalf of the UE to a mandatory network device. The core device can receive a first reply from the mandatory network device indicating success or failure of the third-party registration request, determine a second reply based on the first reply, and transmit the second reply to the UE via the telecommunications network. The core device can process the request and transmit the third-party request if successful. The UE can receive the second reply including status. In response to one status, the UE can retry the registration request via a first access network. In response to another status, the UE can delay for a predetermined time period, and refrain, during the delay, from retrying the registration request via the first access network.