OneLinersCommand workbench
Verified diagnostic signature

PostgreSQL is unreachable or cannot accept another client under the current policy or capacity.

Match output from postgresql, understand the likely cause, then continue with sourced, read-only checks.

Confidence
high
Platforms
linux · macos · windows
Verified
2026-07-24
Recognized output

Signature matched locally

connection to server .* failed: timeout expired

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Likely causes

What usually produces this signal

  1. Listener unavailable
  2. Network timeout
  3. pg_hba policy
  4. Connection exhaustion
Safe next checks

Collect evidence before changing the system

01

Resolve a hostname to its IP address

dig +short <domain>

The output matches the expected target and exits without an error.

02

Check whether a TCP port accepts connections

nc -vz <host> <port>

The output matches the expected target and exits without an error.

03

List listening TCP ports and their processes

lsof -iTCP -sTCP:LISTEN -n -P

The output matches the expected target and exits without an error.

04

Show Linux memory and swap usage

free -h

The output matches the expected target and exits without an error.