Why does the voltage value on the RESET pin of my microprocessor not go high?
If you removed capacitor and MCU now works, and since MCU works after adding a new capacitor, the problem was a faulty capacitor.
It could have been damaged at some point during board manufacture or handling, so it might have a had a microscopic crack, and when pressure is applied (by handling the board or thermal expansion) the capacitor might short out or become leaky.