what does Message: Undefined index: host mean?

I'm running php/codeigniter. could somone give me any clues?

Solution

means that something like $var['host'] was used without being defined beforehand

Closures in PHP... what, precisely, are they and when would you need to use them?
Overriding the "email" attribute on Notifiable Trait Laravel
OCI8 working with the command line but not on apache
How to call custom helper in laravel 5?
How to read specific lines from a text file in PHP
Does PHP have an equivalent to Python's all()
After filtering, check if array is not empty after filtering or has all original values; like Javascript's some() and every()
Why variable can not start with a Number?
How to clone object to child class in php
Make adding custom instrumentation in Sentry less verbose
Multidimensional array sorting by value in php
Sort an array of single-element arrays by value descending and preserve keys
Are there any ways to press the Enter keyboard key?
Sort each subarray of a 2d array by delimited string values
How to get Route name in Laravel 8
Installing oci8 on Centos 8 running Apache and php-fpm
Symfony UX chart does not show chart in easyadmin
Using additional data in php exceptions
I'm trying to format a response from an api but i keep getting Warning: Undefined array key "timestamp"
Distribute child elements from a multidimensional array as rows including parent values in a new 2d array
How to create custom helper functions in Laravel
How do i sort an array of array in PHP?
Process every two elements in a flat array
Cast specific array values to array type
How to Migrate and seed before the full test suite in Laravel with in memory database?
PHP openssl_pkcs12_read "error:0308010C:digital envelope routines::unsupported"
WooCommerce API giving JSON Syntax Error on every request
ERROR: SQLSTATE[HY000] [2002] No connection could be made because the target machine actively refused it
Remove prefix from keys of an associative array and use the prefix as the first level key of a grouped 2d array
Convert numeric words embedded in strings into their integer equivalent, then validate the mutated strings