MinimServer library regularly disappears from menu

[simoncn]

From the symptoms you have described, this is definitely a UPnP multicast discovery problem. The UPnP protocol requires devices to regularly send special messages to keep the connection alive and it sounds like these messages are being blocked by your router.

Are you running MinimWatch as well as MinimServer? If so, does MinimWatch lose contact with MinimServer at the same time that your streamer loses contact? I am asking this because it would be possible to run debug logging on MinimWatch and MinimServer to see exactly what is happening on your network.