I've had similar problems. I suspect it's a combination of a stiff or partially blocked radiator valve. I've replaced 2 of the radiator valves which resolved it. If you have another Kasa TRV, swap...

@anTastico I've had a similar problem and it turned out to be the actual valve on the radiator wasn't capable of being fully closed. I've had to replace 2 and the problem was resolved. You could test...

I have several of these TRV, two of which have updated the firmware to 2.15.0 however one now can be set in 0.5 degree increments and has a valve control feature. The second which updated does not....

@diegomdiniz I would wait... I'm currently running a beta variant of 1.5.1 which seems to be ok so far.. If what you have works, leave it.

@David-TP Swapped the units around following a reset, the problem persists, access denied, the WiFi signal seems to be coming and going. The S7 further away from the router is flashing red, the other...

@David-TP Same issues again. WiFi "access denied" on my tablet when trying to connect to the WiFi. Reset the power, and back on line. I tried to change which S7 wass the main unit in the app, causing...