Notice: Undefined offset: 11462 error when trying to change width of menu

I have added the information to the private content.

The main problem isn’t the notices, the main problem is that it is impossible to save changes to the menu items.
I can accomplish the same by modifying the database, but I want to avoid this if I can.

I have disabled debug mode, and I have tried adding the following to wp-config.php:

ini_set(‘post_max_size’, ‘500M’);
ini_set(‘upload_max_filesize’, ‘500M’);
define(‘WP_MEMORY_LIMIT’, ‘128M’);
ini_set(‘memory_limit’, ‘128M’);
ini_set(‘max_execution_time’, ‘300’);

I also tried adding

php_value session.gc_maxlifetime 10800
php_value max_input_time 10800
php_value max_execution_time 10800
php_value upload_max_filesize 110M
php_value post_max_size 120M

to .htaccess, and I still get the same issue.

I am trying to make the menu items (like Katt) full-width, and it doesn’t work for me. It’s just stuck on Standard width.

I tried doing what you told me to do.

I needed debug mode to be on for development purposes, but I have disabled it again now.

The error messages are gone, but it is not saving the design change, I can still not change, say, the menu “Katt” to be full-width.
It will just not save. It says it has been saved, but the design is still “Standard”, even when I changed it.

I have this in my .htaccess:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ – [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

php_value session.gc_maxlifetime 10800
php_value max_input_time 10800
php_value max_execution_time 10800
php_value upload_max_filesize 210M
php_value post_max_size 220M
php_value memory_limit 256M

# END WordPress

Server provider said it is done in .htaccess.

And since I have php_value post_max_size 220M I assume this should be more than enough?

Yes, that finally fixed the issue!

Thank you very much.