I'm not sure if that is the correct Product category, could be controller as well, so please tell me if it is the wrong category..

I noticed the last days that my router (SDN Controller, running as Docker Contrainer on my Synology NAS) says devices are not online but they clearly are, e.g. my desktop PC.. I made a few test downloads and in the controller my PC does not appear as online..

I have a Netgear managed switch and a 2.5GbE unmanaged TP Link switch, if that matters, but my PC is connected directly to the routers 2.5GbE interface.

I also noticed my NVR NAS (2nd Synology NAS) appears as offline too, even there I'm surprised because it records "external" cameras which always have a connection and data throughput.

E.g. the WI-FI devices connected to my EAPs 772 appear as online when they are online.. also some devices like my Smart Home server is shown always as online as well

Another Information I can give is my PC and the 2 NAS servers have static IPs if that matters (static in the way of address reservation)