If your site is not working properly when the OPcache PHP extension is enabled, it's important to troubleshoot the issue to identify and resolve the underlying problem. Here are steps you can take:

1. Check Error Logs:

   • Look at your server's error logs (e.g., Apache or Nginx error logs) for any error messages or warnings related to PHP or OPcache. This can provide valuable information about what's causing the issue.

2. Verify OPcache Settings:

   • Make sure that the OPcache extension is correctly installed and configured in your php.ini file.

3. Clear OPcache:

   • Sometimes, OPcache may have cached outdated or incompatible files. You can clear the OPcache to force it to recompile the code. You can do this by restarting your web server or using a script to clear the cache.

4. Check for Compatibility:

   • Ensure that your PHP code, including any third-party libraries or frameworks you're using, is compatible with the version of PHP you're running and with the specific version of OPcache.

5. Check for Known Issues:

   • Check if there are any known issues or conflicts with your specific version of PHP and OPcache. Sometimes, certain versions can have compatibility problems.

6. Disable OPcache Temporarily:

   • Temporarily disable OPcache to see if the site starts working. If it does, then the issue is likely related to OPcache.

7. Check Memory Limitations:

   • Ensure that you haven't set overly aggressive memory limits in OPcache. This can sometimes cause issues, especially if you're running on a shared hosting environment with limited resources.

8. Check File Permissions and Ownership:

   • Ensure that the files and directories related to your site have the correct permissions and ownership. Incorrect permissions can sometimes lead to issues.

9. Test on a Local Environment:

   • Try running your site with OPcache enabled on a local development environment to see if the issue persists. This can help determine if the problem is specific to your production server.

10. Check for Extension Conflicts:

• There might be a conflict between OPcache and other PHP extensions. Disable all other extensions and enable OPcache to see if the issue persists. If it doesn't, gradually re-enable the extensions one by one to identify the conflicting extensions.

11. Update or Reinstall OPcache:

    • If you're using an outdated version of OPcache, consider updating it to the latest version. If the issue persists, you might try reinstalling it.

12. Consult Documentation and Forums:

    • Check the official documentation for OPcache and relevant forums or community discussions for any specific issues related to your configuration.

13. Consult with Hosting Provider:

    • If you're on a shared hosting environment, your hosting provider might have specific recommendations or configurations related to OPcache.

14. Seek Professional Help:

    • If you've tried all the above steps and are still experiencing issues, it might be a good idea to consult with a web developer or a system administrator who has experience with PHP and server configurations.

Remember to backup your configurations and files before making any changes, especially if you're working on a production server. This way, you can easily revert back if something goes wrong during the troubleshooting process.