ESA Space Weather Service Network supports end users in a wide range of affected sectors, in mitigating the effects of space weather on their systems, reducing costs and improving reliability. In this network, space weather products and tools are developed and federated in services, that are suitable for operational implementation to meet the end user needs. In the aim to establish a close relationship with the end users of space weather services, the SSA Space Weather Coordination Centre (SSCC) organizes user support campaigns to build tailored space weather bulletins. During the campaign, the SSCC works together with the user in order to compile dedicated space weather forecast notifications. We highlight here the SSCC user support campaign for a group of test users within the GNSS community.