Symptoms:
This issue occurs if the Elasticsearch service is not running or experiencing issues. This can be validated by opening console or ssh session to vRA appliance and running:
service elasticsearch status
To resolve this issue, verify the elasticsearch service status and restart it.
service elasticsearch stop
service elasticsearch start
If the sync logs are still not visible after restarting the elastic search service you can view the elastic search health by running the following command:
curl -XGET 'http://localhost:9200/_cluster/health?pretty=true'
If the health status shows as red under the 'status' field create a support request containing the ouput of command for further assistance.