Warning (2) : Attempt to read property "id" on null [in /var/www/hosting/www.dent.tohoku.ac.jp/html/app/src/Controller/InformationsController.php, line 176]
Warning (2) : Undefined array key 1 [in /var/www/hosting/www.dent.tohoku.ac.jp/html/app/src/Controller/InformationsController.php, line 192]
Warning (512) : Unable to emit headers. Headers sent in file=/var/www/hosting/www.dent.tohoku.ac.jp/html/app/vendor/cakephp/cakephp/src/Error/Renderer/HtmlErrorRenderer.php line=37 [in /var/www/hosting/www.dent.tohoku.ac.jp/html/app/vendor/cakephp/cakephp/src/Http/ResponseEmitter.php, line 71]
Warning (2) : Cannot modify header information - headers already sent by (output started at /var/www/hosting/www.dent.tohoku.ac.jp/html/app/vendor/cakephp/cakephp/src/Error/Renderer/HtmlErrorRenderer.php:37) [in /var/www/hosting/www.dent.tohoku.ac.jp/html/app/vendor/cakephp/cakephp/src/Http/ResponseEmitter.php, line 168]
Warning (2) : Cannot modify header information - headers already sent by (output started at /var/www/hosting/www.dent.tohoku.ac.jp/html/app/vendor/cakephp/cakephp/src/Error/Renderer/HtmlErrorRenderer.php:37) [in /var/www/hosting/www.dent.tohoku.ac.jp/html/app/vendor/cakephp/cakephp/src/Http/ResponseEmitter.php, line 197]
Error: Expression ``Informations`.category_id` is missing operator (IS, IS NOT) with `null` value.

Expression `Informations.category_id is missing operator (IS, IS NOT) with null` value. 📋

InvalidArgumentException
CORE/src/Database/Expression/QueryExpression.php at line 839 (edit)
            $operator '!=';
        }
        if ($value === null && $this->_conjunction !== ',') {
            throw new InvalidArgumentException(
                sprintf('Expression `%s` is missing operator (IS, IS NOT) with `null` value.'$expression)
            );
        }

If you want to customize this error message, create templates/Error/error500.php