- 500 Internal Server Error
- Error Establishing a Database Connection
- White Screen of Death (WSOD)
- 404 Page Not Found Error
- 403 Forbidden Error
- 429 Too Many Requests
- Memory Exhausted Error (Allowed Memory Size Exhausted)
- WordPress Stuck in Maintenance Mode
- Syntax Error or Parse Error
These errors would be considered critical as they typically hinder the functionality of your website.