If you're having trouble connecting to Call of Duty: Black Ops III, you should first check Call of Duty: Black Ops III Server Status. If the status indicator for your platform is not green or an alert is present, you might encounter connectivity issues until service is restored and fully operational.
Adjust the Core Voltage. An undervolted CPU core is one of the most common causes for Black Ops 3 PC not launching. To get rid of the error, we recommend you adjust the Core voltage to lower.