This error usually occurs if there is entry for Primary server in System Configuration > Internal Database Replication > Replication on the secondary server.

For the succesful replication of the database between Primary and Secondary ACS server, refer to this checklist:

On Primary ACS server:

1. You must have the AAA server entry for Primary and Secondary server(s) in the Network Configuration > AAA server section.
   
   
2. You must have the same shared key for both entries Primary and Secondary ACS Server(s).
   
   
3. In the Replication column in System Configuration > Internal Database Replication, the ACS must have the entry of all the secondary servers that ACS wants the replication information to be sent.

On Secondary ACS server(s): 

1. You must have AAA server entry for Primary and Secondary server(s) in Network Configuration > AAA server section.
   
   
2. You must have the same shared key for both entries Primary and Secondary ACS Server(s).
   
   
3. In the Replication column in System Configuration > Internal Database Replication, there should not be any entry there. It should be empty.

Note: ACS does not support bidirectional database replication. The secondary ACS that receives the replicated components verifies that the primary ACS is not on its Replication list. If not, the secondary ACS accepts the replicated components. If so, it rejects the components.

Refer to Important Implementation Considerations section of System Configuration: Advanced for more information.