We are running the enterprise edition on an AWS ubuntu EC2 server, it is a single instance and not a cluster, and has been long running (months) with no problems. We hare recently introduced a system health check which fires ever 30 seconds and together with our normal operations appears to be fine, except occasionally at different/random times 2 of the health checks fail in succession returning a neo4j.exceptions.ServiceUnavailable: Cannot acquire connection to Address(host='[our db]', port=7687).
The next minute and everything is fine again.
I've checked the logs and there are no corresponding errors for the same time, the server remains up, and normal service is immediately resumed for the next check.
We are making the request from another AWS EC2 instance running Django/python with the neo4j driver.