The white screen
Almost always a PHP error, usually from a plugin or theme update, occasionally from a memory limit.
Enable error display in a staging copy, or rename the plugins folder over FTP to confirm it is a plugin. That narrows it immediately.
A slow admin area
- A plugin doing work on every admin page load
- A bloated options table from plugins that never clean up
- Too many revisions on long-lived pages
- Shared hosting under load
Slow admin and a fast front end usually means a plugin. Both slow usually means the server.
Emails not arriving
The default mail function, essentially always. Configure authenticated SMTP and the problem disappears permanently.
It is the single most expensive silent WordPress fault, because the enquiries are lost without any error.
Changes that revert
- Caching — you are seeing an old version, not a reverted one
- Editing a parent theme that gets updated
- Two people editing the same page
- A staging site being confused with live
Sudden traffic drop
| Cause | Check |
|---|---|
| Search visibility switched off | Settings, reading |
| Redirects lost in a redesign | Crawl for 404s |
| Site down intermittently | Uptime monitoring |
| A compromise | Unfamiliar files, unexpected admin users |
| Nothing on your side | Compare against a normal seasonal pattern |