Error: Cannot find dhcpService DN with service reference.

The DHCP server fails to load and you see the following errors in the dhcpd.log file:

dhcpd: Error: Cannot find dhcpService DN  '<a_DHCP_service_and_context>' with server reference. Please update the LDAP server entry '<a_DHCP_server_and_context>'
dhcpd: Error: Confiruation file errors encountered -- exiting

This error is letting you know that there is a disconnect between a service and a DHCP server.

Depending on the cause, there are a few ways to resolve this situation.

Cause: The dhcpService does not exist.
Resolution:

• Launch iManager
• Click the DHCP (OES Linux)->Service role (left pane)
• select "Create Service"
• Create the dhcp service that matches with the error -- '<a_DHCP_service_and_context>'
• Restart the dhcp daemon.  The DHCP server should now load.

Cause: The dhcpService ('<a_DHCP_service_and_context>') does exist but is not associated to the dhcpServer ('<a_DHCP_server_and_context>')
Resolution:

• Launch iManager
• Click the DHCP (OES Linux)->Service role (left pane)
• select "View/Modify Service"
• Select the service in question
  
• Select the proper server in the "Select the Server:" drop down box
• Click "Apply" and then "OK"
• Restart the dhcp daemon.  The DHCP server should now load.

Cause: There are multiple dhcpServices associated to the dhcpServer that will not start (per iManager or dhcp/dns console) -- and at least one of them should not be.
    Also, at least one of the dhcpServices does not show the problemsome dhcpServer as associated.
Resolution:

• Launch iManager
• Click the "View Objects" icon (aka Magnifying Glass) in the top row of icons
  
• Click the "Browse" tab (between Tree & Search tabs)
  
• Browse down to the problem server
• Right click the problem server and select "Modify Object"
  
• Click the "General" tab
• Click "dhcpServiceDn" in the "Valued Attributes" box, and select "Edit..."
• Click the double down arrow icon to display all of the values.
• Select one of the servers that shouldn't be there and press the delete key.  Repeat this step if there are more than one incorrect dhcpService associated.
• Click the double uparrow icon (used to be the double down arrow) to close the pull-down box.
• Click "OK" to save the values and return to the previous screen.
  
• Click "Apply" and then "OK
• Restart the dhcp daemon.  The DHCP server should now load.