WordPress error message and debug.log decoder

Where to find the message

What a visitor sees on a broken page is usually short: "There has been a critical error on this website." The line that says what went wrong is written to a log.

• WordPress's own log is the file debug.log in the wp-content folder. It is written only while WP_DEBUG and WP_DEBUG_LOG are switched on in wp-config.php.
• Your host's PHP error log is in the hosting control panel, often under a name such as "Errors" or "Logs", or in a file named error_log beside the site's files.
• A browser's own message, such as ERR_TOO_MANY_REDIRECTS, can be pasted as it is.

Paste the whole line. The file and the line number at its end are what say which plugin or theme is involved.

What it reads, and what it does with it

The tool looks for messages it knows in what you paste, and for the path of a file. From the path it works out whether the file belongs to a plugin, the theme or WordPress itself. The same message repeated in a log is counted and shown once.

A log can hold the paths of your server and the names of your plugins. That is why this runs in your browser: what you paste is not sent to us, not kept, and not included in anything we measure.

What it cannot tell you

It explains a message. It has not seen your site, so it cannot say why the message appeared today. If the first thing it suggests does not clear the error, the error fixes go through each cause in order.