HKLM\System\CurrentControlSet\services\Netlogon\Parameters

Change the value:

DisablePasswordChange=1

2016-07-21 UPDATE:

Discovered this thread which mentions using PowerShell to reset the machine password, if you haven’t completed the registry change:

Open PowerShell as administrator. Run this command sequence:

$credential = Get-Credential

(enter domain admin account when prompted)

Reset-ComputerMachinePassword -Server <<YOUR DC NAME HERE>>

Thanks to: https://community.spiceworks.com/how_to/108912-fix-the-trust-relationship-between-this-workstation-and-the-primary-domain-failed