Dull red light can be a few different things. Lets try to narrow it down.
Why are you expecting AP mode? Has your WiFi SSID/passkey changed? Did you disconnect it? Did you flash it?
Given one of the above, it will only enter AP mode after a power-on restart. Simply pressing the reset button on the PCB will not do it.
There are two reasons why the light would be dull red during normal (sampling) operation. The most common is WiFi not connected, but the other is that the IoTaWatt doesn’t know what time it is, so can’t log data. If it’s connected to WiFi, the unit should eventually go to green if it can access a time server, also you should be able to access it via iotawatt.local with your browser.
Another failure mode involves problems with the ESP8266 booting from flash. This is very rare, and is usually associated with a failed attempt to flash the device. Have you by any chance tried to do that?
If you have a micro-USB cable and a computer, you can run connect it with that cable and run a serial terminal like Putty (115200 Baud). If it doesn’t print anything when you reset it, then the ESP8266 is either toast or needs a reflash. If it does output anything, I can take a look and probably figure out what’s going on.