MikeP_AutomationManager @ thanks much :)

My other assumption is that I don't have the recent firmware on the plug, though KASA is not showing me any updates.

KASA shows update for the smart plug. How about your Kasa app version? Is it latest?

Anton L.Z. wrote

KASA shows update for the smart plug. How about your Kasa app version? Is it latest?

kasa is version 1.10.2 Build 466, just pulled from apple store. No update shown :(

Also, another question: (maybe not in the best forum topic though) Kasa uses broadcast to find the device each time I start the app, or its directly connecting to the MAC / IP of the device? My network setup is:

192.168.10.0/24 - internal wifi (hidden ssid - more than 8 character long)
192.168.20.0/24 - guest wifi (public ssid - less than 8 character long) -- btw: is there still a limitation of SSID length? I read that this was a problem in the past.

I'm connecting to 192.168.10.0/24 with my phone , and can access the device via http on 192.168.20.0/24, and also can ping, so all ports are accessible from the internal wifi to the guest wifi.
Kasa can't connect to the device for some reason.

so long story short: Kasa and the device must be in the same broadcast domain, or can be in separate routed networks?

In my experience the kasa app and devices need to be in the same broadcast domain to connect locally, but I haven't spent much time investigating it.