This could be for a number of reasons, most commonly, it can be caused by overheating. If you are computer savvy, we recommend downloading a software to check the temps of the computer, such as https://openhardwaremonitor.org/ you can follow our guide linked here. If you are not computer savvy, you can contact our support team and they will be glad to assist. In either case, please do not continue to use your system if you find it is overheating.