connection_failure SSL SYSCALL error: EOF detected — 08006

Symptoms

An SSL/TLS connection failed at the system-call level with an unexpected EOF — the peer closed the socket without a clean TLS shutdown. The driver reports SQLSTATE 08006 (connection_failure).

• The TLS socket hit EOF unexpectedly.
• Often a backend crash or a middlebox resetting the connection.
• Distinct from a TLS negotiation failure.

What the server log shows

ERROR:  SSL SYSCALL error: EOF detected

Why PostgreSQL raises this — what the manual says

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

The TLS layer hit an end-of-file at the system-call level, meaning the underlying TCP connection was closed before the SSL session ended cleanly — usually a crashed backend, a firewall reset, or an abrupt network interruption.

An EOF detected SSL SYSCALL error means the TCP socket carrying the TLS session was closed abruptly (no close-notify). The encrypted session cannot continue, so the client reports 08006.

Common causes

• A backend crash/termination on the encrypted session.
• A firewall/load balancer resetting the connection.
• Network instability dropping the TLS socket.

How to fix it

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

Related & next steps

• SQLSTATE 08006 — Connection Failure (full reference)
• Message: SSL connection has been closed unexpectedly
• Glossary: SSL/TLS

Reference: PostgreSQL 18 Section 19.9 “SSL”.