To troubleshoot an issue with a Active Directory domain controller having incorrect time, you should:

1. Check the connectivity of the DC: Verify that the DC has access to the internet and valid DNS configurations.
2. Check the Windows Time Service: Check that the Windows Time Service is running and is configured to an appropriate time zone and synchronization option.
3. Verify the time source: Check to see if the server is using the correct time source.
4. Verify the CMOS battery: Check the motherboard battery to ensure it is functioning as intented.
5. Verify any additional applications: If the DC is running any additional applications, check those to see if they have any impact on the DC’s time.