As a trusted provider of Cloud Server, CDN, S3 Storage, Streaming, and WAF solutions in Vietnam, EVG summarizes the most common server errors, their root causes, and the best solutions to address them efficiently.

1. 500 Internal Server Error

Causes: The 500 error is among the most common server issues. It occurs when the server encounters an unexpected condition that prevents it from fulfilling the request, without specifying the exact cause. Common reasons include:

• Syntax errors in code (e.g. PHP, Python)

• Misconfigured .htaccess file

• Server overload or misconfiguration

• Incorrect file permissions

Solutions:

• Check and fix errors in the .htaccess file.

• Ensure proper folder/file permissions (usually 755 or 644).

• Review the server error logs to identify the issue.

• If using EVG Cloud Server, restart the web service (Apache/Nginx) from the control panel.

2. Server Overload (High Load)

Causes: This error occurs when server capacity is exceeded, often due to:

• Traffic spikes (from ads or flash sales)

• Unoptimized code or heavy database queries

• System resources (RAM, CPU) consumed by unnecessary tasks

Solutions:

• Optimize application code and database queries.

• Use EVG CDN to offload traffic and improve speed.

• Upgrade Cloud Server resources (RAM, CPU).

• Enable auto-scaling if supported.

3. Database Connection Error

Causes: This error appears when the server fails to connect to the database (MySQL, PostgreSQL, etc.). Possible causes include:

• Incorrect connection credentials (host, user, password)

• Database server is down

• Too many simultaneous connections

Solutions:

• Verify database connection settings in the configuration file.

• Restart the MySQL/PostgreSQL service.

• Check database error logs.

• Set connection limits or implement connection pooling.

4. DNS Errors

Causes: DNS errors happen when domain names fail to resolve to an IP address due to:

• Incorrect DNS settings (CNAME, A record)

• Expired or updating domain

• Incomplete DNS propagation

Solutions:

• Double-check DNS settings with your domain registrar.

• Use tools like dnschecker.org to monitor propagation.

• For EVG users, ensure the domain points to the correct Cloud Server IP.

5. 403 Forbidden Error

Causes: This occurs when access to a resource is denied. Common reasons include:

• File or folder permissions set to deny access

• IP addresses or user-agents blocked by the server

• Misconfigurations in .htaccess

Solutions:

• Check folder/file access permissions.

• Review .htaccess rules or web server configuration.

• Ensure your WAF or firewall isn’t blocking valid traffic.

6. 502 Bad Gateway

Causes: This error appears when a proxy or load balancer fails to receive a valid response from the upstream server:

• Backend server crash

• Server timeout due to slow response

• Misconfiguration between proxy and backend

Solutions:

• Check the backend server status.

• Increase timeout limits in proxy settings (Nginx, Apache).

• Restart the relevant services.

7. 504 Gateway Timeout

Causes: Similar to 502 errors, this happens when the server takes too long to respond:

• Complex queries slowing down the backend

• Overloaded server

• Timeout settings in proxy are too short

Solutions:

• Optimize backend logic and queries.

• Increase timeout values in server configuration.

• Use caching (e.g. EVG CDN, Redis/Memcached) to reduce load.

8. SSL Certificate Errors (HTTPS Security Issues)

Causes:

• Expired SSL certificate

• Incorrect HTTPS setup

• Self-signed certificates not trusted by browsers

Solutions:

• Renew and install valid SSL certificates.

• Verify HTTPS and Virtual Host configurations.

• Use certificates from trusted providers like Let’s Encrypt or Comodo.

9. How to Prevent Server Errors Proactively

Instead of waiting for errors to occur, businesses should take preventive actions to build a robust server infrastructure:

EVG Cloud Solutions for Stability and Security:

• EVG Cloud Server: High performance, 99.99% uptime, scalable resources

• EVG CDN: Reduces server load and improves global access speed

• EVG WAF: Protects web applications from threats like SQLi and XSS

• EVG S3 Storage: Automatic and secure backup storage

24/7 Monitoring: Real-time alerts and expert support team

Conclusion

Understanding and resolving common server issues is crucial for maintaining a stable, efficient IT infrastructure. By leveraging EVG’s suite of cloud solutions, your business can minimize downtime, enhance user experience, and ensure seamless digital operations with confidence.