Troubleshoot 500 Errors.

Troubleshoot 500 Errors.

Main Server Inaccessibility Error

A common issue users of VergeCloud's accelerated and secured websites may encounter is the "Main Server Inaccessible" error. This error indicates that the primary server is temporarily unavailable. VergeCloud displays this message when the origin server returns one of the following error codes: 500, 502, 503, or 504.

Understanding 502 and 504 Error Codes

502 Error Code: Bad Gateway

The 502 error occurs when VergeCloud's edge server receives an invalid response from the main server of the website. Possible causes include:

  • Website main server is inaccessible: This might happen due to sudden traffic surges overwhelming the server, causing disruption in the connection between the VergeCloud edge server and the website’s main host server.
  • Firewall blocking requests: Some firewalls may block requests from VergeCloud's edge server, particularly in cases of overly sensitive DDoS mitigation settings.
  • Blocked services or applications: The requested service or application may be restricted on the main server.

Fixing Error 502

To resolve the 502 error, you can perform the following actions on your website’s main server:

  • Use tools like ping or traceroute to check the server's accessibility.
  • Review firewall logs for any unusual request drops or blocked connections.

504 Error Code: Gateway Timeout

The 504 error is displayed when VergeCloud's edge server doesn’t receive a response from the main server within the allocated time. Possible causes include:

  • Inaccessibility or server issues: The website’s main host server may be unavailable or experiencing functional problems.
  • Firewall blocking requests: Requests between VergeCloud's edge server and the main server may be dropped due to restrictive firewall settings.

Fixing Error 504

To resolve the 504 error, consider the following steps:

  • Add VergeCloud's IP addresses to the whitelist on the firewall and server-side limits.
  • Ensure the main host server is operational and accessible.

While Ping and Traceroute are useful tools for testing server accessibility, MTR provides more advanced insights into network performance and connectivity.

Key Points About the Main Host Server Inaccessibility Error

  • This error usually points to an issue with the website’s main server, not VergeCloud.
  • It is often a temporary problem that may affect only a subset of users for a short period before resolving automatically.
  • Issues may stem from communication links between the hosting data center and the server, rather than the server itself.
  • This is generally not a security concern but rather an issue related to heavy traffic, network link problems, or server accessibility.
  • If the ports on the main server are blocked (e.g., HTTP port 80 or HTTPS port 443) while using VergeCloud’s default connection settings, this error may occur. To fix this, navigate to the CDN settings in the VergeCloud panel and select the correct protocol for your main server connection, such as HTTPS.

Customizing Error Pages

VergeCloud allows users to replace default error pages with custom error pages. To set up custom error pages, follow these steps:

  1. Log in to your VergeCloud panel.
  2. Navigate to Content Distribution Network (CDN) settings.
  3. Select the Customize Errors option.
  4. Upload your custom error page design to provide a personalized user experience.

Considerations

  • Ensure that VergeCloud’s IP addresses are whitelisted on your firewall to avoid unnecessary request drops.
  • Always test changes made to server configurations to ensure proper communication between VergeCloud and your main server.
  • Monitor server performance and traffic surges to anticipate potential inaccessibility issues.
  • When enabling custom error pages, verify that they conform to VergeCloud’s upload and format guidelines.

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