SSL connection has been closed unexpectedly

Symptoms

An SSL/TLS-encrypted connection was closed unexpectedly without a clean shutdown. The driver reports SQLSTATE 08006 (connection_failure).

• The encrypted connection dropped abnormally.
• Often a backend crash/restart or network drop on a TLS session.
• Distinct from a TLS negotiation failure.

What the server log shows

SSL connection has been closed unexpectedly

Why PostgreSQL raises this — what the manual says

As Section 18.9 Secure TCP/IP Connections with SSL explains:

An encrypted (SSL/TLS) connection was torn down without a clean close-notify handshake — commonly caused by the peer process crashing, a network drop, or an idle/keepalive timeout closing the socket mid-session.

On a TLS connection, an abrupt break (without a proper close-notify) leaves the SSL session terminated unexpectedly. The client cannot continue and reports 08006.

Common causes

• A backend crash, restart, or failover on a TLS session.
• Network instability or a middlebox resetting the connection.
• TLS renegotiation/timeouts on long-idle encrypted sessions.

How to fix it

1. Reconnect and retry; handle dropped encrypted connections gracefully.
2. Check the server log for crashes/terminations.
3. Investigate network devices/load balancers and keepalive/idle settings.

Related & next steps

• SQLSTATE 08006 — Connection Failure (full reference)
• Message: server does not support SSL, but SSL was required
• Glossary: SSL/TLS

Reference: PostgreSQL 18 Section 19.9 “SSL”.