Replacing ELTAKOs by Shelly Dimmer2 seems to be not adequate if Dimmer2 is operated in dual button mode! Usually, the ELTAKO are controlled by one button at each place the lights should be switched…
eltako was there with one led and 5 buttons, I had replaced the eltako with shelly 1l and it was fine but Recently I've installed some dimmable leds and replaced the 1L with Dimmer2 and it was working for a week. I don't know what has happened. 😢
edit: I have found the problem. I installed a button wrong. now it works again. thank you