ElasticSearch Couchbase Replication Issue

I have a problem with my ElasticSearch cluster in Couchbase XDRC configuration.

I put private ip 10.28.0.21 as IP ( my elasticsearch and couchbase in the same server) when creating cluster reference. Then the system change that by public IP (92.222..) of my server. It is very strange. I dont know why ?

Couchbase log show :

Updated remote cluster 'ElasticSearch' hostname to "92.222..:9091" because old one ("10.28.0.21:9091") is not part of the cluster anymore

Thanks for any suggestion.