Use this information to troubleshoot multiple data center configurations, including linking between catalog service domains.
Solution: You can troubleshoot this problem with the xscmd -c showLinkedPrimaries command. This command prints out each primary shard, and including which foreign primaries are linked.
In the described scenario, you might discover from running the xscmd -c showLinkedPrimaries command that the first catalog service domain primary shards are linked to the second catalog service domain primary shards, but the second catalog service domain does not have links to the first catalog service domain. You might consider rerunning the xscmd -c establishLink command from the second catalog service domain to the first catalog service domain.