Warning (2) : Attempt to read property "id" on null [in /home/gdhsystem/public_html/plugins/DesignLab/src/Controller/PublicController.php, line 76]
Warning (512) : Unable to emit headers. Headers sent in file=/home/gdhsystem/public_html/vendor/cakephp/cakephp/src/Error/Renderer/HtmlErrorRenderer.php line=37 [in /home/gdhsystem/public_html/vendor/cakephp/cakephp/src/Http/ResponseEmitter.php, line 65]
Warning (2) : Cannot modify header information - headers already sent by (output started at /home/gdhsystem/public_html/vendor/cakephp/cakephp/src/Error/Renderer/HtmlErrorRenderer.php:37) [in /home/gdhsystem/public_html/vendor/cakephp/cakephp/src/Http/ResponseEmitter.php, line 159]
Warning (2) : Cannot modify header information - headers already sent by (output started at /home/gdhsystem/public_html/vendor/cakephp/cakephp/src/Error/Renderer/HtmlErrorRenderer.php:37) [in /home/gdhsystem/public_html/vendor/cakephp/cakephp/src/Http/ResponseEmitter.php, line 192]
Error: Expression `DesignLabProjects.design_lab_id` is missing operator (IS, IS NOT) with `null` value.

Expression `DesignLabProjects.design_lab_id` is missing operator (IS, IS NOT) with `null` value. 📋

InvalidArgumentException
CORE/src/Database/Expression/QueryExpression.php at line 748 (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