When a website shows a blank page or an error code, the cause is almost always written in a log file. Plesk's Log Browser collects the Apache, Nginx and PHP-FPM logs for each domain in one place, with search and real-time updates. Knowing how to read it saves hours of guesswork.
Before you start
- Access to the domain in Plesk.
- The approximate time the error happened and the URL that failed.
Open the Log Browser
- Go to Websites & Domains.
- Under the domain, click Logs.
You see recent entries from all of the domain's logs, newest first. Each line shows the time, the source (Apache, nginx, PHP), the IP address, the status code and the request or message.
Filter what you see
- Use the log type buttons to show only Errors (Apache error log, nginx error log, PHP errors) or Access entries.
- Type in the search box to filter by URL, IP address or error text.
- Click the status code column to group, for example all 500 responses.
- Click Real-time update (the play icon) and reload the failing page; new lines appear immediately.
- Click Manage Log Files to download a full log or view older, rotated files.
Read common errors
| Code or message | Usual cause |
|---|---|
| 500 + "PHP Fatal error" | A plugin or code bug; the line shows the file and line number |
| 500 + "Invalid command" / ".htaccess" | Unsupported directive in .htaccess |
| 502 Bad Gateway | PHP-FPM or a proxied app (Node.js, Docker) is down or crashed |
| 503 + "server reached pm.max_children" | Too many concurrent PHP requests; raise the limit or add caching |
| 504 Gateway Timeout | A script runs longer than the proxy timeout |
| 403 + "AH01630 client denied" | Access rules, ModSecurity or file permissions |
| 404 in bulk from one IP | A scanner looking for vulnerable files |
Show PHP errors temporarily
If a page is blank and the log is quiet, set display_errors to on in the domain's PHP settings, reload the page to see the message, then switch it off again. For WordPress, you can instead set WP_DEBUG and WP_DEBUG_LOG to true in wp-config.php.
Log rotation
Under Logs → Manage Log Files → Log Rotation you can rotate by size or time and keep a number of old files, compressed. This prevents logs from filling the disk quota. Administrators may enforce limits for all subscriptions.
Troubleshooting
- No entries at all: the request may not reach the server (DNS or Cloudflare). Check with
curl -I https://example.com. - ModSecurity blocks: look for "ModSecurity: Access denied" with a rule ID. Administrators can switch off that rule under Tools & Settings → Web Application Firewall.
- Logs are huge: enable rotation and compression, and check for a bot hammering a URL.