Web / WordPress

WordPress

WordPress guides and diagnostics for critical errors, plugins, themes, SMTP, permalinks, PHP, security and performance.

Error 500PluginsSMTPPermalinksPHPSecurityElementor

4BAOI modules

25selected resources

6definitions

Tools & diagnostics

Direct access to the most relevant BAOI modules for this technology.

Troubleshooting WordPress Center

WordPress diagnostic: critical error, 500, database, permalinks, SMTP, cron, plugins, WordPress, SSL and performance.

Open → Troubleshooting WordPress site in error

Diagnostiquez un site WordPress en erreur : codes HTTP, extensions, thème, PHP, base de data, journaux et mode de récupération.

Open → Troubleshooting Email & SMTP Center

Diagnosis SMTP, Microsoft 365, Infomaniak, TLS, SPF, DKIM, DMARC, MX, relay, PTR and WordPress.

Open → Troubleshooting Hyper-V Center

Diagnostic Hyper-V : VM, VHDX, checkpoints, vSwitch, migration, Replica, Failover Cluster, CSV et PowerShell.

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Dictionary

Essential concepts related to WordPress.

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Dictionary Block Theme WordPress

A WordPress component or mechanism used to structure content, rendering, or site administration.

View → Dictionary WordPress Transients

A mechanism WordPress temporary storage of data with expiry.

View → Dictionary WordPress transient

A transient temporarily stores a cached data in WordPress.

View → Dictionary WordPress Block

A WordPress component or mechanism used to structure content, rendering, or site administration.

View → Dictionary Template Part WordPress

A WordPress component or mechanism used to structure content, rendering, or site administration.

View → Dictionary WordPress Custom Post Type

A WordPress component or mechanism used to structure content, rendering, or site administration.

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Practical guides

Step-by-step tutorials and procedures.

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Guide How to disable a WordPress plugin without access to wp-admin

Quickly disable an extension that causes a fatal error when the WordPress administration is not more accessible.

View → Guide How to put WordPress in maintenance mode without plugin

Understand the.maintenance file used by WordPress during some updates.

View → Guide How to analyze a WordPress redirect loop

The redirect loops often come from a disagreement between WordPress, proxy, HTTPS and cache.

View → Guide How to activate WordPress debug logs

Save WordPress errors to a log file without showing them to visitors.

View → Guide How to Increase WordPress PHP Memory

Reasonably add the memory limit available for WordPress when, a memory error the requires.

View → Guide How to recover WordPress after a plugin critical error

When wp-admin is inaccessible after the, activation or update of a plugin, the safest way is to disable only the suspicious plugin via the file system.

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Troubleshooting

Related failures, errors and diagnostics.

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Error code WordPress — Error establishing a database connection

WordPress does not manage to connect to its database.

View → Error code WordPress — The site is experiencing technical difficulties

WordPress detects a fatal error and displays a recovery page.

View → Resource WordPress.com vs WordPress.org: What difference?

WordPress.com is a hosted service with several offers. WordPress.org is the free WordPress software that you are evaluating at the host of your choice.

View → Troubleshooting WordPress displays « A critical error occurred »

WordPress encounters a fatal PHP error and can no longer normally display a page or the administration.

View → Troubleshooting WordPress displays an error 500

The server returns HTTP 500 when accessing the WordPress site.

View → Troubleshooting WordPress no longer connects to the database

WordPress displays "Error when connecting to the database".

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Field procedures

Reusable intervention methods.

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Procedure Solve a fatal WordPress error

Recover WordPress after critical error without masking the cause: Recovery Mode, PHP/WP_DEBUG_LOG, Targeted deactivation, WP-CLI, version verification and…

View → Procedure Configure SMTP email sending from a WordPress site

Configure WordPress to send through authenticated SMTP with an aligned sender, correct Reply-To, SPF, DKIM and DMARC alignment, connectivity testing, and l…

View → Procedure Redirect an old domain to a new WordPress site

Migrate an old domain to a new WordPress site without losing paths by keeping HTTPS on both domains, defining a URL mapping, issuing server-side 301 redire…

View → Procedure Secure a compromised WordPress site

Treating a compromise WordPress as an incident: preserve the evidence, contain, check the checksums, rebuild from reliable sources, clean the base, turn th…

View → Procedure Gradually migrate Wi-Fi from WPA2 to WPA3

Migrate a WPA2 SSID to WPA3 with customer inventory, transition mode, PMF, driver, incompatibility measurement and progressive removal of WPA2 fallback.

View → Procedure Fix an SMTP 550 Sender mismatch error

Fix an SMTP 550 Sender mismatch by aligning the authenticated SMTP account, visible From address, envelope MAIL FROM, aliases or delegations, and WordPress…

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Cheat sheets

Quick references for operations.

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Cheat sheet WordPress — Express troubleshooting

Incident-focused WordPress reference for logs, plugins, themes, database, WP-CLI, cron, permalinks, SMTP, permissions and 500/critical errors.

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Defensive resources for phishing, ransomware, compromised accounts, MFA, hardening, firewalls, incidents and backup protection.

View → Technology Microsoft 365

Microsoft 365 administration and troubleshooting for Entra ID, Exchange Online, Intune, OneDrive, SharePoint, MFA and email.

View → Technology IT Networking

Tools and methods for DNS, DHCP, VLANs, routing, Wi-Fi, switching, TCP/IP, latency, MTU and network diagnostics.

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