sqlserver_rejected_establishment_of_sqlconnection Sqlserver Rejected Establishment Of Sqlconnection — SQLSTATE 08004

The server actively rejected the connection during startup.

• The error is written to the server log and returned to the client carrying SQLSTATE 08004.
• Any driver (libpq, JDBC, psycopg, npgsql, pgx) surfaces this code in its error object so you can branch on it programmatically.
• PL/pgSQL can trap it by name: EXCEPTION WHEN sqlserver_rejected_establishment_of_sqlconnection THEN.

Severity: ERROR  |  PostgreSQL versions: 12, 13, 14, 15, 16, 17

Commonly coincides with restarts, failover, maintenance, or network events; check server uptime and the log around the timestamp.

The server received the request but refused it before or during authentication.

Common causes:

• No matching pg_hba.conf rule for this host/database/role.
• The target database does not exist.
• max_connections is reached (see 53300).
• The role lacks the LOGIN attribute.
• The server is in recovery and not yet accepting connections.

Steps to resolve 08004:

1. Read the exact reason in the server log — it names the failing rule or limit.
2. Add or correct the pg_hba.conf entry and reload: SELECT pg_reload_conf();.
3. Verify the database and login role exist and the role has LOGIN.
4. If slots are full, add pooling or raise max_connections (see 53300).

Reference: PostgreSQL error codes — Class 08 (Connection Exception).