🛠️ Fixing (HTTP ERROR 500) PHP Website Blank / White Page / Internal Server Error

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For cPanel + CloudLinux + LiteSpeed + Webuzo

📖 Introduction

Seeing a white page or HTTP 500 Internal Server Error when visiting your PHP website means that something is broken—but PHP is hiding the error output by default. This is common in hosting setups that use cPanel, CloudLinux, LiteSpeed, or Webuzo, where errors are logged rather than displayed.

🔁 Common Causes:

  • PHP memory limit exhausted
  • Incompatible or missing PHP modules/extensions
  • Syntax or runtime errors in scripts
  • Corrupt or blank index.php or .htaccess
  • Wrong PHP version or handler
  • File permission or ownership issues

🔍 Step-by-Step Troubleshooting

📁 1. Locate PHP Error Logs

✅ cPanel (No PHP-FPM):

/home/$cpuser/public_html/error_log

✅ cPanel with PHP-FPM (CloudLinux default):

/home/$cpuser/logs/

✅ LiteSpeed (if integrated with cPanel):

Also check:

/usr/local/lsws/logs/error.log

✅ Webuzo:

Logs may be in:

/var/webuzo/users/$cpuser/webapps/$domain/error_log

📟 2. Monitor Logs in Real-Time

Run the following to catch the error while reloading the site:

tail -f -n0 /home/$cpuser/public_html/error_log

If using PHP-FPM:

tail -f /home/$cpuser/logs/php-fpm/error.log

If using LiteSpeed global log:

tail -f /usr/local/lsws/logs/error.log

🧪 3. Temporarily Show Errors On-Screen

For debugging only, add this at the top of index.php or the problematic file:

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

⚠️ Never leave these on in production.

⚙️ 4. Check PHP Configuration

cPanel & CloudLinux:

Use selectorctl to check or change user PHP settings:

selectorctl --get-current --user=$cpuser

List available versions:

selectorctl --list-available

Change version for a user:

selectorctl --set-user-current=8.1 --user=$cpuser

Check and enable missing PHP extensions:

Via CLI:

selectorctl --enable-extensions=mbstring,pdo,mysqli --user=$cpuser

Or via cPanel > Select PHP Version GUI.

🧱 5. File and Permission Checks

  • Ensure PHP files are 644 and directories are 755
  • File ownership should match the cPanel user: chown -R $cpuser:$cpuser /home/$cpuser/public_html

📑 6. Fix .htaccess and Routing Issues

  • Rename .htaccess temporarily: mv /home/$cpuser/public_html/.htaccess /home/$cpuser/public_html/.htaccess.bak
  • If the error disappears, regenerate .htaccess from CMS settings (e.g., WordPress Settings > Permalinks).

🚫 7. Fix Memory Limit / Timeout / Execution Issues

Edit .user.ini or use MultiPHP INI Editor (cPanel) to increase values:

memory_limit = 512M
max_execution_time = 120

To reload PHP-FPM:

/scripts/restartsrv_apache_php_fpm

For LiteSpeed:

/usr/local/lsws/bin/lswsctrl restart

🧰 8. Webuzo-Specific Tips

Webuzo panel has its own error_log location per app:

/var/webuzo/users/$cpuser/webapps/$app/error_log

Also check Webuzo PHP settings via:

Webuzo Admin Panel > Server Settings > PHP Settings

Or use the terminal:

php -v
php -m

✅ Final Checklist

CheckDescription
✅ LogsError appears in error_log
✅ PHP VersionCompatible with your app
✅ ModulesRequired extensions enabled
✅ MemorySufficient memory limit
✅ PermissionsCorrect ownership and chmod
✅ .htaccessValid and uncorrupted
✅ SyntaxNo PHP code errors

📝 Conclusion

HTTP 500 or blank PHP pages are almost always due to server-side misconfigurations or suppressed fatal errors. Using this guide across cPanel, CloudLinux, LiteSpeed, and Webuzo, you should be able to identify the exact issue quickly.

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