When you demote the first domain controller in a site, your Application event log contains:
Event ID: 213
Description: Replication of license information failed because the License Logging Service on server <ServerName> could not be contacted.
The licensing server for the site cannot be contacted by the computer on which the event is generated.
To resolve this problem:
1. Open Active Directory Sites and Services.
2. Select the site on which the computer is located.
3. Select Licensing Site Settings in the right-hand pane.
4. Press Properties on the Action menu.
5. Under Licensing Computer, Change the licensing server for the site.