@hockey41 Thanks for your response. And for others as well... You gave me a solid way to find the device. Since I've posted this message I turned off the notifications. Thank you all for your help.

I sent the support an email about that and other things (firewall, connecting to the deco locally through the app when there's no internet and a few suggestions). I hope to get a response back soon...

Every day i get a notification about an unknown device got connected to / disconnected from the router. When i look at the device list I don't see that device. I named every device on my device list...