Hi,
Have you checked that the wall outlet that the device’s power adapter is connected to is working?
If the adapter is plugged into a powerboard (powerstrip?) try connecting it directly to the wall outlet and see if it now works OK.
If the wall outlet is OK use a DMM (digital multimeter - voltmeter function) to check that the M8S pro’s power adapter is supplying 5V DC power, or if you have a compatible adapter (5VDC / 2A output) with the correct size plug try using that and check if it turns on
If the wall outlet is OK and the adapter is supplying the 5V DC, how old is the device?
Check the warranty and if it is still within the manufacturer's warranty period, follow the directions in the warranty on how to make a claim for a manufacturer's warranty repair or replacement.
If it is no longer in warranty, then the device will need to be opened and the problem further investigated as to why it doesn't start.