Over the past three years, we have seen this happen very infrequently, and it would usually resolve itself after about 10 minutes. However, after we upgraded to NMS7.6, running NAS version 4.37, this is a much more frequent occurrence and the system does not recover by itself. Alarm assignments, acknowledgements and new alarm updates stop working in Infrastructure manager after about 14-18 hours of runtime. To fix, we have to restart several hubs in our infrastructure, including the primary hub. Users are connecting to a hub that is connected via a tunnel connection to the primary hub (the IM clients are 3 hops away from the primary hub). Has anyone else experienced these symptoms?