Method enabling an application server to acknowledge, with a single acknowledgement frame, a set of frames sent by endpoints in a group of endpoints to said application server. Each endpoint in said group communicates with the application server via a gateway and a centralising server. The application server is connected to the centralising server via a first communication network. The centralising server is connected to each gateway by a second communication network. The group of endpoints and each gateway form a LoRa network, each communication between an endpoint in said group and a gateway using the LoRaWAN protocol.