Common WordPress errors often share a small number of causes: an incompatible update, exhausted server resource, incorrect URL or rewrite configuration, database failure, cache issue or external-service interruption. Use the symptom to choose a safe first check, but confirm the cause before applying a permanent fix.
Quick diagnostic table
| Symptom | First checks | Avoid |
|---|---|---|
| Critical error / blank page | Recovery Mode email, PHP/server log, latest change | Deleting random plugins or showing errors publicly |
| Error establishing database connection | Host status, credentials, database service and disk/resource state | Repeatedly editing the database without a backup |
| 404 on inner pages | Permalink/rewrite configuration and server rules | Redirecting every missing URL to the homepage |
| Changes not visible | Browser, page, server and CDN cache; correct environment | Repeatedly editing content before clearing the right cache |
| Login loop or locked out | Correct URL, cookies, account recovery and security controls | Disabling all protection without preserving access/logs |
| 500/502/503 response | Server logs, resource limits, upstream status and recent deployment | Assuming every 5xx response is a WordPress plugin bug |
| Scheduled tasks not running | Cron model, queues, traffic dependence and host scheduler | Running failed jobs repeatedly without finding the cause |
Critical error after an update
Use the Recovery Mode link if WordPress generated one. Identify the named plugin, theme or custom code in the error information. On staging or through a controlled file-access route, disable the suspected component and confirm the site returns. Preserve the version and logs so the supplier can investigate.
Database connection failure
Confirm the database service and hosting account are healthy before editing credentials. Check whether disk space, resource limits or a migration changed connection details. The public message does not prove that the database is lost; it means WordPress could not complete the connection.
404 and redirect problems
Determine whether the server receives the correct URL, whether WordPress permalinks are configured and whether rewrite rules are active. For a migration, verify home/site URLs and redirects. Do not use blanket search-and-replace on serialized WordPress data without a compatible tool and a backup.
The site works for administrators but not visitors
Compare logged-in and logged-out cache, consent, security and personalisation rules. Test a private browser and a real phone. Administrator sessions often bypass cache and security layers, hiding public failures.
Email and forms appear successful but no message arrives
Check whether the form stored the submission, whether WordPress handed the message to the mail route, and whether the receiving service accepted it. Separate form validation, mail transport and inbox filtering; changing the form plugin may not solve a delivery problem.
Escalate with useful evidence
- Exact URL, time and timezone
- User role/device and steps to reproduce
- HTTP status and full error text with secrets removed
- Recent changes and versions
- Relevant log excerpt
- What has already been tested and its result
- Current backup and rollback status
What not to do during an outage
- Do not publish server paths, logs, credentials or database details.
- Do not restore an old shop database without protecting recent orders.
- Do not delete the suspected extension before preserving its version and settings.
- Do not clear every cache and log before evidence is collected.
- Do not give unknown support contacts unrestricted administrator access.
Each action should be reversible or have a documented recovery path.
Practical next step
Choose the row matching the current symptom and perform only the first non-destructive checks. Record the result before deactivating, restoring or changing configuration.
Sources and date checked
This guide was checked on 21 July 2026. WordPress, plugins, hosting platforms and commercial terms change, so confirm the current documentation and licence details before making a material change.
Keep the decision under your control
Retain the relevant accounts, source material, supplier terms and recovery information. Recheck changing prices, interfaces and rules before acting.