Always Free ATP database randomly stops and restarts

Summary

My ATP databases stop and start unprompted at seemingly random times.

Content

An ATP database I use for development (ocid1.autonomousdatabase.oc1.iad.abuwcljsj7u6vmks5zyvbu7xjfcsrreirbodnqhhmksreswb33ihi75plkta) was offline today. Looking at the traffic graphs, it seems to have been arbitrarily powering off and back on over the past couple of weeks.

What could be causing this?

Version

n/a