Database handshake failed from RDS Proxy to RDS Postgres Instance in Cluster

Question

I have a Postgres Cluster and the connection to instance #1 fails with database handshake failing. The other two instances are TargetHealth:State:AVAILABLE.  Is this instance's server corrupt?

```
aws rds describe-db-proxy-targets --db-proxy-name foo

....
  "Type": "RDS_INSTANCE",
            "Role": "UNKNOWN",
            "TargetHealth": {
                "State": "UNAVAILABLE",
                "Reason": "CONNECTION_FAILED",
                "Description": "Database handshake failed"
            }
```

Answer

The TLS handshake to the proxy failed. Some possible reasons include the following:
* SSL is required but the server doesn't support it.
* An internal server error occurred.
* A bad handshake occurred.

https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/rds-proxy.troubleshooting.html

"Database handshake failed" error doesn't definitively indicate server corruption.

If you suspect corruption and cannot resolve the issue through configuration changes or restarts, consider restoring the instance from a backup. AWS RDS allows you to restore to a point in time or from a snapshot, minimizing data loss.

Database handshake failed from RDS Proxy to RDS Postgres Instance in Cluster

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