The replication of certificates from the central management store to the local machine failed due to a problem with encryption key management. Skype for Business Server 2015, Replica Replicator Agent will continuously attempt to retry the replication. While this condition persists, the certificates on the local machine will not be updated.
The encryption key database has been corrupted or local machine cannot access it.
Ensure that forest configuration is up to date. Run Enable-CSAdForest and/or Enable-CSComputer Power Shell commands to validate forest and local machine configuration.