MY printer won't heat up.

MY printer won’t heat up. I am connected via octoprint and can control the movement, but if I set something to print it sets a target temperature but stays at room temp. I have used gcode which has worked for me before. Do you have any suggestions please?

interestingly if I set the temperature manually in octoprint it heats up fine. As i say the gcode I’ve used before doesn’t work now. I think it also isn’t extruding. Now that I can get the temperature up manually it just moves the head about but doesn’t extrude, again I can force it manually.

This is most strange. You can use OctoPrint UI to set temperature. What this does is really just send a set of G-codes to Arduino. Can you try use OctoPrint’s UI to send the same G-code and heat up the head?