I have 3 such modules and have successfully flashed them all with emonESP-master a couple of weeks ago.
Two modules have been working since then in my test rig.
I’ve just tried to hook up the third module but have a problem – I can browse to its IP address but am asked for a username & password which I can’t recall. The default username/password does not work.
I tried putting it in AP mode but could not connect to 192.168.4.1.
I re-flashed with emonESP-master but still the same problem.
Any suggestions please.
There should not be any password by default, however maybe a web interface password was set accidently.
You could use esptool to fully erase the flash including the config, then re-upload the emonESP firmware
sudo ./esptool.py --port /dev/ttyUSB0 erase_flash