CI4 session_write_close() when redirect

PHP Code:

->with('validation', $validation) 


You can't save $validation in the session like that. It's an instance of the validation library, that's why it crashes in session_write_close().

Here is an example to send the error messages to the redirected page. Use validate() to validate the rules, then use validator to get the error messages.
You can see a detailed example in this tutorial: https://includebeer.com/en/blog/how-to-b...r-4-part-6

PHP Code:

if ( ! $this->validate($rules))
{
    return redirect()->back()->withInput()->with('errors', $this->validator->getErrors());
}