Most reseller clients run WordPress, and most of their problems are the same few.
WHITE SCREEN
Enable WP_DEBUG logging in wp-config.php and read wp-content/debug.log. Otherwise rename wp-content/plugins to disable everything and reintroduce them one at a time.
ERROR ESTABLISHING A DATABASE CONNECTION
Compare wp-config.php against the database details in cPanel. Remember the cPanel username prefix on both database and user names.
500 ERROR
Check cPanel > Metrics > Errors. Rename .htaccess and re-save permalinks. Check the PHP version.
404 ON EVERY PAGE BUT THE HOMEPAGE
Settings > Permalinks > Save. That regenerates the rewrite rules.
SCHEDULED POSTS AND UPDATES NOT RUNNING
HTTP wp-cron is blocked on our servers. The account needs DISABLE_WP_CRON in wp-config.php and a real cron job calling wp-cron.php with the PHP binary. Set this up as part of your standard account provisioning and you will avoid a recurring class of ticket entirely.
SITE SLOW
Enable LiteSpeed Cache, optimise images, remove unused plugins, update PHP. In that order.
