wow, that looks fantastic!

several things:

• it should be accessToken (with 2 s)
• it should be lists: [‘inbox’],
• did you really add ‘Access Token’ and ‘ClientID’ as text to the values? You should just provide the token and the clientid without any other text or signs

like this:

getDom: function() {
	var wrapper = document.createElement("div");
	if(this.dataFile){
		var humidityRegExp = /Humidity = (.*?) %/ig;
		var humidity = humidityRegExp.exec(this.dataFile)[1];

		var temperatureRegExp = /Temperature = (.*?) *C/ig;
		var temperature = temperatureRegExp.exec(this.dataFile)[1];

		var spacer = document.createElement("span");
		spacer.innerHTML = " ";
		var temperature_symbol =  document.createElement("span");
		temperature_symbol.className = "fa fa-home";
		var humidity_symbol =  document.createElement("span");
		humidity_symbol.className = "fa fa-tint";

		wrapper.appendChild(temperature_symbol);
		var temperature_text = document.createElement("span");
		temperature_text.innerHTML = " " + temperature + "°C";
		wrapper.appendChild(temperature_text);

		wrapper.appendChild(spacer);

		wrapper.appendChild(humidity_symbol);
		var humidity_text = document.createElement("span");
		humidity_text.innerHTML = " " + humidity + "%";
		wrapper.appendChild(humidity_text);
	} else {
		wrapper.innerHTML = "No data";
	}
	return wrapper;
},

Should give you a house symbol for temperature inside and a droplet for humidity.

getDom: function() {
	var wrapper = document.createElement("div");

	var symbol =  document.createElement("span");
	symbol.className = "fa fa-home";
	wrapper.appendChild(symbol);

	return wrapper;
}

This will result in a “house symbol”

Open the configuration file (in bash type sudo nano /boot/config.txt) and look for disable_overscan
This is either commented with a # or set to 0
It should be disable-overscan=1
Be sure to look through the whole file, sometimes this setting appears more than once.

Reboot your pi and you should be good

Hm, maybe you could try this.
Put the file in the modules folder and open it with “./Test-temp.txt“
Additionally i would suggest to go with lowercase during testing to exclude case sensitive mistakes.

If you start the magic mirror with “npm start” in the console, do you see any error messages?

Wow, the microwave approach sounds good. Will this work behind the mirror?