I am sorry you are having this problem with the product but let me help you.
At this point, I am having problems to find the model you mentioned but maybe you are referring to DC3217BY. Based on your description it may be possible that the board is malfunctioning and causing this issue but there are some steps you can try first:
1. Test a supported Operating System (windows versions)
2. Update the BIOS in your system to the latest:
3. Try a different power supply.
4. Clear the CMOS on the NUC. Here you have the instructions.