This issue occurs because the dual Network Interface Card (NIC) host is not supported on the CiscoSecure ACS for Microsoft Windows.
When the CiscoSecure ACS for Windows is installed on a server PC with two NICs, it stops replication.
The workaround for this issue is to disable one NIC when the database is replicated from one CiscoSecure ACS for to another.
For replication between ACS servers, you need to verify these:
Verify that your servers all run exactly the same ACS version and build. You can verify this at the bottom of the window when you first login.
Next, check to make sure that you do not send or receive the distribution table. On the primary server, the distribution table needs to not be checked in the send list, and on the secondary, the distribution table needs to not be checked for receive.
Then check in the partner list of the secondary server in order to make sure that it is blank. You should not enter any servers into the partner list on the secondary server. But, the primary server needs to have all secondary servers listed in its partner list.
Finally, ensure that the secondary server has the replication scheduling set to manual.