@Alexandre. Yeah, thats a good idea. I just tested by unplugging a Satellite Deco, then connecting to it - and it worked. So it could be the switch. The switch is a Netgear G5205...

@Alexandre. Problem is i don't have a managed switch between the M9s, i am case 1 - which should "just work" but isn't. So i don't even get the option to set the vnet on the satellites when i try to...

Same issue as reported here: https://community.tp-link.com/us/home/forum/topic/99275 wondering if this is a known issue? setup is: M9pro --wired--> M9pro x 2 all the guests I can see in the deco app...