Common Errors

This guide covers the most common errors you’ll encounter and how to fix them. Use Ctrl+F / Cmd+F to search for your specific error message.

White Screen of Death (WSOD)

Symptoms: Blank white page with no content or error messages.

Causes & Solutions:

1. PHP Fatal Error

   # Check PHP error logs
   tail -f /var/log/apache2/error.log
   # Or
   drush watchdog:tail
   

2. Memory Limit Exceeded

   # In settings.php or settings.local.php
   ini_set('memory_limit', '512M');
   

3. Module Conflict

   # Disable recently installed modules
   drush pmu module_name -y
   drush cr
   

4. Corrupted Cache

   # Clear all caches
   drush cr
   # Or via database if Drush fails
   drush sql-cli
   TRUNCATE TABLE cache_bootstrap;
   TRUNCATE TABLE cache_render;
   exit
   

Prevention:

• Enable error reporting in development: $config['system.logging']['error_level'] = 'verbose';
• Always test module updates on staging first

Permission Denied Errors

Error: Warning: file_put_contents(sites/default/files/...): failed to open stream: Permission denied

Solutions:

1. Fix File Permissions

   # Set correct ownership (replace www-data with your web server user)
   sudo chown -R www-data:www-data sites/default/files
   
   # Set correct permissions
   sudo chmod -R 755 sites/default/files
   

2. SELinux Issues (CentOS/RHEL)

   # Check SELinux status
   getenforce
   
   # Set correct SELinux context
   sudo chcon -R -t httpd_sys_rw_content_t sites/default/files
   

3. Temporary Fix (Development Only)

   chmod 777 sites/default/files
   # NEVER use 777 in production!
   

Composer Dependency Conflicts

Error: Your requirements could not be resolved to an installable set of packages.

Solutions:

1. Update Composer

   composer self-update
   composer --version  # Should be 2.0+
   

2. Clear Composer Cache

   composer clear-cache
   composer update --no-cache
   

3. Check PHP Version

   php -v  # Should match composer.json requirements
   

4. Use Specific Versions

   # Instead of ymca/website-services:*
   composer require ymca/website-services:^11.1
   

5. Diagnose Conflicts

   composer why-not ymca/website-services 11.1.0
   composer prohibits ymca/website-services 11.1.0
   

Database Update Failures

Error: Exception: ... in update hook

Solutions:

1. Backup First!

   drush sql-dump > backup-$(date +%Y%m%d).sql
   

2. Run in Safe Mode

   # Skip problematic hooks
   drush updb --entity-updates -y
   

3. Check Error Logs

   drush watchdog:show --severity=Error
   

4. Manual Fix

   # Mark update as complete manually (last resort)
   drush sql-cli
   INSERT INTO key_value (collection, name, value)
   VALUES ('system.schema', 'module_name', 's:4:"9001";');
   exit
   

Need more help? See Debugging Techniques or Get Support.