I bought the printer a few days ago, unfortunately it doesn't feel like starting a print. Every time I select a print, it heats up, goes through its position routine and places the head in the right place. As soon as the print bed and print head reach the pre-set temperature and it should start printing, it sets all temperatures to 0, starts to cool down and the progress bar goes from 0% to 100% in about 15 seconds and stops printing without moving on. I have managed to start a print twice so far, but since then every attempt with example models like the boat or the rabbit and also own and downloaded models is unsuccessful. Since I don't get an error message and I can't find anything on the internet about this behaviour, it is quite difficult to find the error. As this is my first 3D printer I am not very experienced yet. I have set up the printer step by step and straightened the bed, the plugs are also plugged in correctly. When I move the print head via the menu, I can only move it upwards on the Z axis, when I want to move it downwards, it does not move. What can I do? Have I received a faulty product?