Intermittent database errors usually indicate resource exhaustion or unstable connections.
High traffic, slow queries, or limited database connections are common triggers.

Check database server logs and monitor connection limits. Optimizing queries and reducing plugin load often stabilizes connections.

Hosting-level issues, especially on shared environments, can also cause this behavior.

The mistake is focusing only on credentials instead of performance.
The takeaway is that database reliability depends on both configuration and workload.