Hi and welcome to JustAnswer,Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially, let's start with the basic / preliminary tries (if have not been done):
All others would require inspection of the internal circuitry and would most likely need the use of a multi-meter.
Is this a fresh/new install? ...or has it been in use for some time and this issue only recent?
If connected to WiFi, please re-check wireless network/connection.