I have a Shelly 1 in a Shelly Button. It worked perfectly, until I had to remove power for a short period while getting the Christmas lights in order.
Now it can't connect to WiFi anymore.
I tried resetting it to factory defaults (power off/on and then press the button 5 times) and then I can connect to the AP (tried both via web interface and via the Shelly app). As soon as I enter my own Wifi details and save, it won't connect to the network.
I had a fixed IP set in my router based on the MAC address, but I removed all settings connected to the Shelly, so that shouldn't be a problem.
Wifi of the Shelly works when it is in AP mode, so that should also not be the problem. Wifi connection is fine at the location of the Shelly.
Any suggestions?