Fatal Error: Cannot Use Object of Type WP_Error as Array

Why it happens

• A plugin or theme asked WordPress for something, the call failed, and the code then read the answer as an array ($response['body']). A failed call returns a WP_Error object, and PHP cannot read an object like an array.
• The failed call is most often an outgoing web request: wp_remote_get() or wp_remote_post(). The server could not look up the host (cURL error 6), could not connect (7), timed out (28), or WP_HTTP_BLOCK_EXTERNAL blocks outgoing requests in wp-config.php.
• Many other core functions return a WP_Error too: get_the_terms() and get_terms() for a taxonomy that does not exist, wp_insert_term() for a name that exists, wp_insert_post() called with its error flag, wp_create_user() for a taken user name.
• It is a bug in the plugin or theme, even when something outside it started the failure. Code that makes a web request has to cope with the request failing.

How to fix it

Try the fixes in this order. Each one is independent: stop as soon as the error is gone.

Some code on your site made a request or a lookup, and it failed. The code did not check, and read the answer as a list of values. A failed WordPress call gives back a WP_Error, which holds the failure and has no values to read, so PHP stops the page. The plugin or theme named in the message is the one to switch off. The failed call underneath is what you fix.

What you see#

On a live site, PHP's message is hidden and WordPress shows its general page. The status is 500, and every page that runs the code is affected:

With errors shown (many local and staging sites), you get the real message, with the file and line of the code that made the mistake:

I made this with a five-line plugin that shows a currency rate from a web service. The plugin is a stand-in for any plugin that fetches data. Outgoing requests were blocked in wp-config.php:

add_shortcode( 'eur_rate', function () {	$response = wp_remote_get( 'https://api.example.com/rates.json' );	$data     = json_decode( $response['body'], true );   // line 7: the fatal error	return 'EUR: ' . esc_html( $data['EUR'] );} );

The wp-admin screens kept working, because the shortcode only runs when a page that holds it is shown. That is why you can often still log in to fix it.

How one call gives two kinds of answer#

wp_remote_get() has two possible return values. A request that finished gives an array, even when the answer is an error page. A request that could not be made or did not finish gives a WP_Error object.

WP_Error does not implement PHP's ArrayAccess, so square brackets are not allowed on it. I tested every way to use brackets on a WP_Error in PHP 8.3:

The message is not new with PHP 8. I ran the same code on PHP 7.4.33, 8.1.34 and 8.3.36 and got the same Error each time. Since PHP 7 these failures are Error exceptions, and an uncaught one ends the request with "Fatal error: Uncaught Error". That is what makes the plugin crash instead of only warn.

What the WP_Error says#

The WP_Error has a code and a message. These are the ones I got from wp_remote_get() on WordPress 7.1.4, one per cause:

A server that answers with 404 gave a plain array, not a WP_Error:

dns      WP_Error  http_request_failed | cURL error 6: Could not resolve host: no-such-host.invalidrefused  WP_Error  http_request_failed | cURL error 7: Failed to connect to 127.0.0.1 port 9 after 0 ms: Could not connect to servertimeout  WP_Error  http_request_failed | cURL error 28: Operation timed out after 1006 milliseconds with 0 bytes received404      array     code=404 message=Not Found body=not found200      array     code=200 message=OK body={"EUR":0.92}

So is_wp_error() alone is not a full check. The 404 reply passes it, and its body is not the data you wanted. Check the status code as well.

The check that fixes it#

add_shortcode( 'eur_rate', function () {	$response = wp_remote_get( 'https://api.example.com/rates.json' );	if ( is_wp_error( $response ) ) {		error_log( 'Rates Widget: ' . $response->get_error_code() . ': ' . $response->get_error_message() );		return 'EUR: not available right now';	}	if ( 200 !== wp_remote_retrieve_response_code( $response ) ) {		error_log( 'Rates Widget: HTTP ' . wp_remote_retrieve_response_code( $response ) );		return 'EUR: not available right now';	}	$data = json_decode( wp_remote_retrieve_body( $response ), true );	if ( ! is_array( $data ) || ! isset( $data['EUR'] ) ) {		return 'EUR: not available right now';	}	return 'EUR: ' . esc_html( $data['EUR'] );} );

Each failure now shows the fallback text, the page stays up, and the debug log keeps the reason:

[30-Oct-2026 12:05:23 UTC] Rates Widget: http_request_not_executed: User has blocked requests through HTTP to the URL: https://api.example.com/rates.json.[30-Oct-2026 12:05:26 UTC] Rates Widget: HTTP 404[30-Oct-2026 12:05:30 UTC] Rates Widget: http_request_failed: cURL error 6: Could not resolve host: rates.invalid

The fix works because it moves the failure to a place the code controls. The call can still fail, and it will. The page just no longer depends on it.

The same error from other functions#

The web request is the most common source, not the only one. These all returned a WP_Error in my tests, and indexing the result with [0] gave the same fatal error:

Two details are worth knowing. wp_insert_post( array() ) without the true flag does not return a WP_Error. It returns 0. And a foreach over a WP_Error does not fail. It loops over the object's own properties, so you get two array values with the keys errors and error_data, and no terms. That bug shows up later as a different warning.

When it is not your code#

If the plugin comes from wordpress.org or a vendor, you cannot fix its code in a way that lasts. Do this:

1. Switch the plugin off and get the site back (fix 2).
2. Find why the call fails (fixes 3 and 4). Often the failure is a setting on your server, not the plugin.
3. Tell the plugin's developer the file and line from the message, and that the code needs is_wp_error() after the call. That is a precise report they can act on in minutes.
4. Update the plugin when they ship the fix, using the steps in how to update plugins safely.

If the plugin will not activate at all, see plugin could not be activated. If your site shows the critical error page and you cannot tell which plugin it is, see there has been a critical error on this website.