When loading the dashboard I am seeing this error message below the footer.

How can this be resolved?

An Error occurred while handling another error:
yii\web\HeadersAlreadySentException: Headers already sent in /app/web/_protected/vendor/koolreport/dashboard/Response.php on line 176. in /app/web/_protected/vendor/yiisoft/yii2/web/Response.php:369
Stack trace:
#0 /app/web/_protected/vendor/yiisoft/yii2/web/Response.php(342): yii\web\Response->sendHeaders()
#1 /app/web/_protected/vendor/yiisoft/yii2/web/ErrorHandler.php(136): yii\web\Response->send()
#2 /app/web/_protected/vendor/yiisoft/yii2/base/ErrorHandler.php(152): yii\web\ErrorHandler->renderException(Object(yii\web\HeadersAlreadySentException))
#3 [internal function]: yii\base\ErrorHandler->handleException(Object(yii\web\HeadersAlreadySentException))
#4 {main}
Previous exception:
yii\web\HeadersAlreadySentException: Headers already sent in /app/web/_protected/vendor/koolreport/dashboard/Response.php on line 176. in /app/web/_protected/vendor/yiisoft/yii2/web/Response.php:369
Stack trace:
#0 /app/web/_protected/vendor/yiisoft/yii2/web/Response.php(342): yii\web\Response->sendHeaders()
#1 /app/web/_protected/vendor/yiisoft/yii2/base/Application.php(390): yii\web\Response->send()
#2 /app/web/public_html/index.php(19): yii\base\Application->run()
#3 {main}

<?php
//App.php

namespace app\reports;

use koolreport\dashboard\Application;
use koolreport\dashboard\inside\Yii2;


class App extends Application
{
    use Yii2;

    protected function onCreated()
    {
        $this->title('AHG Reports');
        $this->debugMode(true);

    }

    protected function sidebar()
    : array
    {
        return [
            "Members"=>MemberTable::create()->icon("fas fa-users"),
        ];
    }
}

<?php
namespace app\controllers;

use app\reports\App;
use yii\web\BadRequestHttpException;
use yii\web\Controller;

require_once __DIR__ .  "/../vendor/autoload.php";
require_once __DIR__ . "/../../_protected/reports/App.php";

class NewReportsController extends Controller
{
    public function beforeAction($action)
    : bool {
        $this->enableCsrfValidation = false;
        try {
            return parent::beforeAction($action);
        } catch (BadRequestHttpException $e) {
            return false;
        }
    }

    public function actionIndex()
    {
        App::create()->run();
    }
}

I am able to see the Dashboard now on initial load, HOWEVER when I click a pagination button, back button on detailAction, or search on the dashboard it just gives this error.

This is the MemberTable.php that is called.

That did it. I could have saved days of investigation if this was put into your docs for installation. Please do that for others. Thank you so much.