List of all CRITICAL errors but not the BLOCKER error
In IT, software, hardware, networking, cloud, and enterprise systems, Critical errors are severe issues that significantly impact functionality but do not completely block the entire application or business. They often require immediate attention but usually have a workaround or affect only part of the system.
Below is a comprehensive list.
| Error Type | Category | Why Critical (Not Blocker) |
|---|---|---|
| Application Crash | Software | App crashes during specific operations only |
| Memory Leak | Software | Gradually consumes memory causing instability |
| High CPU Usage | Performance | System becomes slow but still works |
| High Memory Usage | Performance | Performance degradation |
| Disk Space Critical | Hardware/System | Low disk space affecting operations |
| Database Connection Failure | Database | Some features unavailable |
| Database Timeout | Database | Queries fail intermittently |
| Deadlock Detected | Database | Transactions stuck |
| Data Corruption (Partial) | Database | Some records damaged |
| Service Unavailable (Single Service) | Infrastructure | One microservice down |
| API Failure | Integration | External API unavailable |
| Authentication Failure | Security | Users unable to login |
| Authorization Failure | Security | Access denied unexpectedly |
| SSL Certificate Expired | Security | Secure communication affected |
| Token Expired Loop | Security | Session unusable |
| File Upload Failure | Software | Upload feature broken |
| File Download Failure | Software | Downloads fail |
| Configuration Error | Configuration | Incorrect config impacts functionality |
| Dependency Failure | Software | Required library/service unavailable |
| Third-party Service Failure | Integration | Payment, Email, SMS unavailable |
| Queue Processing Failure | Messaging | Background jobs stop |
| Cache Server Failure | Infrastructure | Increased latency |
| Redis Connection Failure | Infrastructure | Session/cache issues |
| Message Broker Failure | Infrastructure | RabbitMQ/Kafka unavailable |
| DNS Resolution Failure | Network | Some services unreachable |
| Network Latency High | Network | Slow communication |
| Packet Loss | Network | Intermittent failures |
| Gateway Timeout (504) | Network | Requests timeout |
| Bad Gateway (502) | Network | Upstream failure |
| Internal Server Error (500) | Software | Server exception |
| Service Timeout | Infrastructure | Service doesn’t respond |
| Thread Pool Exhausted | Performance | Requests delayed |
| Resource Starvation | System | CPU/RAM exhausted |
| Process Hung | Software | Process stops responding |
| Scheduler Failure | System | Scheduled jobs missed |
| Cron Job Failure | System | Automation interrupted |
| Backup Failure | Infrastructure | No recent backup |
| Replication Failure | Database | Replica outdated |
| Failover Failure | Infrastructure | High availability compromised |
| Storage I/O Error | Hardware | Read/write problems |
| RAID Degraded | Hardware | One disk failed but array alive |
| Disk Read Error | Hardware | Slow or failed reads |
| File System Corruption | Hardware/System | Some files inaccessible |
| Temperature Warning | Hardware | Device overheating |
| Fan Failure | Hardware | Cooling degraded |
| Power Supply Degraded | Hardware | One PSU failed (redundant remains) |
| Network Interface Failure | Hardware | One NIC down |
| Certificate Validation Failure | Security | Secure API calls fail |
| Encryption Failure | Security | Data cannot encrypt/decrypt |
| Session Management Failure | Security | Users logged out repeatedly |
| Email Delivery Failure | Communication | Notifications unavailable |
| SMS Gateway Failure | Communication | OTP delivery affected |
| Push Notification Failure | Mobile | Alerts not delivered |
| Payment Gateway Failure | Business | Purchases fail |
| License Validation Failure | Licensing | Premium features disabled |
| Cloud Storage Failure | Cloud | Files inaccessible |
| CDN Failure | Cloud | Static assets unavailable |
| Object Storage Timeout | Cloud | Upload/download issues |
| Kubernetes Pod CrashLoop | Cloud | Service instability |
| Container Restart Loop | Cloud | Frequent service interruptions |
| VM Resource Exhaustion | Cloud | Instance overloaded |
| Autoscaling Failure | Cloud | Traffic spikes unmanaged |
| Log System Failure | Monitoring | Logs unavailable |
| Monitoring Agent Failure | Monitoring | Health metrics missing |
| Alerting Failure | Monitoring | Critical alerts not sent |
| Time Synchronization Failure | Infrastructure | Authentication/token issues |
| Index Corruption | Search | Search results incorrect |
| Search Service Failure | Search | Search unavailable |
| Data Sync Failure | Integration | Systems out of sync |
| Import/Export Failure | Software | Data transfer interrupted |
| Permission Sync Failure | Identity | Incorrect user permissions |
| Mobile App Freeze | Mobile | UI stops responding |
| ANR (Application Not Responding) | Android | App becomes unresponsive |
| Excessive Battery Drain | Mobile | Poor user experience |
| Background Task Failure | Mobile | Sync not working |
| GPS Failure | Mobile | Location unavailable |
| Camera Initialization Failure | Mobile | Camera feature unavailable |
| Microphone Access Failure | Mobile | Recording fails |
| Bluetooth Connection Failure | Mobile | Device pairing fails |
| WebSocket Disconnect | Network | Real-time updates stop |
| Session Timeout Error | Web | User sessions terminate unexpectedly |
| Rate Limit Exceeded | API | Requests temporarily rejected |
| Serialization Failure | Software | Data conversion fails |
| Deserialization Failure | Software | Invalid object parsing |
| Version Compatibility Error | Deployment | Client/server mismatch |
| Migration Failure | Database | Schema update incomplete |
| Rollback Failure | Deployment | Deployment recovery unsuccessful |
| Feature Flag Failure | Deployment | Wrong features exposed |
| Audit Logging Failure | Security | Compliance logs missing |
| Data Validation Failure | Software | Invalid business data processed |
Common Critical HTTP Errors
| HTTP Code | Meaning |
|---|---|
| 500 | Internal Server Error |
| 502 | Bad Gateway |
| 503 | Service Unavailable |
| 504 | Gateway Timeout |
| 507 | Insufficient Storage |
| 508 | Loop Detected |
| 429 | Too Many Requests |
| 408 | Request Timeout |
| 409 | Conflict |
| 422 | Unprocessable Entity |
Examples of Critical (but Not Blocker)
- Payment gateway is down, but users can still browse products.
- Search feature fails while the rest of the website works.
- Email notifications are not being sent, but transactions complete.
- One database replica fails while the primary database continues serving requests.
- Mobile app crashes only when opening the camera.
- Background synchronization stops, but users can still use the application.
- High CPU usage causes slow response times, but requests eventually complete.
- Redis cache is unavailable, but the application falls back to the database.
These issues are typically classified as Critical (Severity 2) because they have a major impact but do not cause a complete outage. A Blocker (Severity 1) would be something like the entire application being unavailable, total database failure, or a production issue that prevents all users from using the system.