Learn how to fix GraphQL Internal Server errors in Plesk. Our Plesk Support team is here to help you with your questions and concerns.

How to Fix GraphQL Internal Server Error in Plesk

GraphQL errors typically occur on the server side when executing a GraphQL operation. We can classify these errors into three categories:

• Syntax Errors:

  These happen when the query is malformed, making it unreadable by the GraphQL parser.
• Validation Errors:

  These occur when a query references a schema field that does not exist.
• Resolver Errors:

  These arise when an error occurs while fetching data for a specific query field.

When a syntax or validation error occurs, the server does not execute the operation because it is considered invalid. However, if a resolver error occurs, the server can still return partial data, depending on the error’s severity.

Today, we will look at the causes behind the 500 Internal Server Error in GraphQL and how to resolve them.

500 Internal Server Error in GraphQL

The HTTP 500 Internal Server Error is a common response status code indicating that the server encountered an unexpected condition preventing it from fulfilling the request. This generic error response signifies that the server cannot find a more specific 5XX error to return.

Some of the common reasons for a 500 error in GraphQL include:

• Improper server configuration
• Out-of-memory (OOM) issues
• Unhandled exceptions in resolver functions
• Incorrect file permissions
• Corrupt or inconsistent database records

Investigating 500 Errors in Plesk

A 500 Internal Server Error can indicate an issue preventing the server from processing a GraphQL request in a Plesk environment. Common symptoms include:

• Inability to access Tools & Settings > Database Servers
• Errors logged in `/var/log/plesk/panel.log`, such as:

  ERR [panel] Dependent row(s) 'Domains.id = 10455' isn't found for 'data_bases.dom_id = 10455'.

Solutions

1. Increase Execution Limits

Adjusting execution time can help resolve timeout-related errors:

1. Log into Plesk UI.
2. Navigate to Domains > example.com > PHP Settings.
3. Increase the `max_execution_time`.

2. Modify Apache & Nginx Settings

Add the following directives under Domains > example.com > Apache & Nginx settings > Additional directives for HTTP and HTTPS to optimize server performance:


Timeout 600
ProxyTimeout 600


3. Clear Browser and Server Cache

Sometimes, cached configurations may cause conflicts. Try:

• Refreshing the page
• Clearing the browser cache
• Restarting the web server
• Clearing the GraphQL cache (if applicable)

4. Repair the Database

If inconsistencies in the database are causing the error, follow these steps:

1. Connect to the server via SSH.
2. Run a database repair command:

   plesk repair db -y

5. Backup and Remove Corrupt Database Entries

1. Create a Plesk database backup:

   plesk db dump psa > psa_$(date +%F-%s).sql
2. Identify missing domain databases:

   plesk db -Ne "SELECT name FROM data_bases WHERE dom_id=1029"
3. Drop the problematic databases:

   
plesk db "DROP DATABASE example_db"
plesk db "DROP DATABASE example_db2"

4. Clean up the referencing entries:

   plesk db "DELETE FROM data_bases WHERE dom_id=1029"

6. Verify File Permissions

Incorrect file or directory permissions can prevent the GraphQL server from processing requests. Ensure that necessary files and directories have the correct ownership and permissions.

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Conclusion

By systematically diagnosing and addressing potential causes, we can easily troubleshoot GraphQL-related 500 Internal Server Errors in Plesk. Regular database maintenance, server optimization, and cache management can help prevent these issues from recurring.

In brief, our Support Experts demonstrated how to fix GraphQL Internal Server error in Plesk.