Unfortunately, WordPress is hiding the actual error message and gives us no way to see it. Without it, we can't possibly know what is going on. So, before we do anything else, we have to convince it to show us this message.
Create the file wp-content/mu-plugins/debug.php with the following contents:
<?php
add_filter(
'wp_php_error_message', function ($message, $error) {
$theMessage = $error['message'] ?? '(no message)';
$file = $error['file'] ?? '(no file)';
$line = $error['line'] ?? '(no line)';
$context = <<< HTML
<div style="border: thick solid red; border-radius: 1em; padding: 1em; margin: 1em 0;">
<h4 style="margin: 0 0 0.75em">$theMessage</h4>
<p style="margin: 0">$file:$line</p>
</div>
HTML;
return $context . $message;
}, 10, 2
);
Edit your wp-config.php file and find the WP_DEBUG line. Replace it with:
define('WP_DEBUG', true);
define('WP_DEBUG_DISPLAY', true);
define('WP_DEBUG_LOG', true);
Now retry what you did before. You will get a more detailed error message. Copy it here so I can help you.
Afterwards, you can remove the the file wp-content/mu-plugins/debug.php and comment out the three lines in the wp-config.php file by placing // in front of each line.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!
