Referring to a post in the shelly community forum for a nearly identical issue on a mini 1 g3 I have just had the same occur on a g4.
In summary, the issue is that if you mistkenly put the incorrect DNS (0.0.0.0 the first time) in the DNS field of your Wifi setup, it fails to come up ever again. Nor does the backup wifi save it, if enabled. When you're 9500km away that is heartbreaking.
User error? Absolutely, but surely, surely Shelly devs, if the Wifi connectivity fails, could it not revert to last know good config or release the DNS paramter and allow it to connect after a certain time of no connection, after X retries? For my last one the g4, I have no idea what I put in there (I thought it was 192.168.63.1, same as Gateway). Whatever it was, maybe just one number out IDK, it caused complete failure.
Be interetsed to see if anyone else has ever had this issue? Restoring ii is easy, after a reset - if you are there...
