Hello,
Thank you for reaching out to us at Microsoft Community Forum.
Along with questions asked by Shawn (MVP), which will help us in diagnosing the exact cause of the issue, I would recommend that you run Power troubleshooter.
You can run the Power troubleshooter to adjust your computer's power settings. The Power troubleshooter checks things like your computer's timeout settings, which determine how long the computer waits before turning off the monitor display or entering sleep mode.
Refer to the link provided below for information on how to run the Power troubleshooter.
Hope this information is helpful.