@VolkerS If you go to settings and LAN, edit one of the networks, go to advanced settings, it is not there, then your router is not compatible with the new setting.

@VolkerS upgrade router firmware manualy, the latest version does not notify you in the omada console...

@VolkerS It's not certain that you have it, do you have the latest version on your controller and router? Try and upgrade your router to the latest version first

@VolkerS enable ARP Detection on network interface, adavanced settings

@Alfred_DOMO you have to run enable first then roll-back

@VolkerS yes that was strange, SG2428P should show you the ip address of the clients, i have such a switch myself. have you tried restarting everything, switch access points and controllers. you can...