Low memory causes blank pages and "allowed memory exhausted" errors.

1. Edit wp-config.php in your site's root via File Manager (article 111).
2. Above the line that says /* That's all, stop editing! */, add: define('WP_MEMORY_LIMIT', '256M');
3. Save the file.
4. If that isn't enough, also raise PHP's memory_limit in cPanel (article 64).

Tip: 256M is plenty for most sites. If you still hit limits, a plugin is likely the cause — review and reduce them.