Fix Connection Errors

This guide helps you diagnose and fix database connection errors.

Common Error: Connection Refused

Error:

Connection refused (localhost:5432)

Causes:

  • Database server not running

  • Wrong host or port

  • Firewall blocking connection

Solutions:

  1. Check if database is running:

# PostgreSQL
pg_isready -h localhost -p 5432

# MySQL
mysqladmin -h localhost -u root ping
  1. Start the database:

# PostgreSQL (macOS with Homebrew)
brew services start postgresql

# PostgreSQL (Linux)
sudo systemctl start postgresql

# MySQL
sudo systemctl start mysql
  1. Verify connection string:

Common Error: Authentication Failed

Error:

Solutions:

  1. Verify credentials:

  1. Reset password (PostgreSQL):

  1. Check pg_hba.conf for authentication method

Common Error: Database Does Not Exist

Error:

Solutions:

  1. Create the database:

  1. For SQLite, ensure directory exists:

Common Error: Too Many Connections

Error:

Solutions:

  1. Close unused connections

  2. Increase connection limit:

  1. Use connection pooling

Common Error: SSL Required

Error:

Solutions:

Add SSL mode to connection string:

Debugging Connection Issues

Test Connection Script

Run:

Check Network Connectivity

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