Issue 1: Permalink Changes Cause 404s on Every Post
One of the most repeated patterns is changing permalink structure and suddenly getting 404s on posts while the homepage still works. In most cases, the root cause is rewrite handling: missing or stale .htaccess, disabled rewrite module, or Apache not allowing overrides.
- Ensure Apache rewrite is enabled:
sudo a2enmod rewrite - Confirm your vhost directory has
AllowOverride All - Regenerate rewrite rules by saving Permalinks in WP Admin
- Restart Apache and test a known post URL
Issue 2: wp-admin Redirect Loop After SSL/Proxy Changes
Another common thread is “too many redirects” after introducing SSL, reverse proxying, or mixed Nginx/Apache routing. Usually this is a scheme/proxy mismatch where WordPress and upstream disagree about HTTP vs HTTPS.
- Verify reverse-proxy headers are passed correctly
- Confirm canonical site URL values and force a single scheme
- Clear page/object cache before retesting login flows
- Temporarily disable conflicting redirect/security plugins
Issue 3: “Error Establishing a Database Connection”
This message appears in many variants, but the same checks solve most of them: invalid credentials, wrong host/port, DB service outage, or socket-vs-TCP mismatch. Treat this as a connectivity problem first, not a theme/plugin issue.
- Re-check
DB_NAME,DB_USER,DB_PASSWORD, andDB_HOSTinwp-config.php - If your DB uses a non-default port, set
DB_HOSTaccordingly (for example127.0.0.1:3307) - Validate credentials manually:
mysql -h 127.0.0.1 -P 3307 -u USER -p - Check DB service health and restart only after root-cause review
Issue 4: White Screen / Blank Pages After Update
White-screen incidents are usually fatal PHP errors hidden by production settings. Typical triggers are plugin/theme incompatibility, incomplete file deploys, or missing template files after manual changes.
- Enable temporary debug logging in non-public logs
- Switch to a default theme to isolate template faults
- Disable all plugins and re-enable one by one
- Verify full core file integrity before deeper tuning
Production Workflow That Prevents Repeat Incidents
In hosted WordPress environments, the fastest recovery path is a consistent sequence:
- Take a Proxmox snapshot or verified backup before risky changes
- Apply one configuration change at a time
- Check logs after each change, not at the end of a long batch
- Keep rollback criteria explicit (latency, 5xx rates, admin access)
- Document final fix and add preventive monitoring
Authoritative Docs to Keep Handy
Internal references: Technology, Security, and incident response checklist.
