An Error occurred while handling another error:
yii\web\HeadersAlreadySentException: Headers already sent in /var/www/html/models/Sitemap.php on line 64. in /var/www/html/vendor/yiisoft/yii2/web/Response.php:368
Stack trace:
#0 /var/www/html/vendor/yiisoft/yii2/web/Response.php(341): yii\web\Response->sendHeaders()
#1 /var/www/html/vendor/yiisoft/yii2/web/ErrorHandler.php(136): yii\web\Response->send()
#2 /var/www/html/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 /var/www/html/models/Sitemap.php on line 64. in /var/www/html/vendor/yiisoft/yii2/web/Response.php:368
Stack trace:
#0 /var/www/html/vendor/yiisoft/yii2/web/Response.php(341): yii\web\Response->sendHeaders()
#1 /var/www/html/vendor/yiisoft/yii2/base/Application.php(660): yii\web\Response->send()
#2 /var/www/html/models/Sitemap.php(65): yii\base\Application->end()
#3 /var/www/html/controllers/SiteController.php(184): app\models\Sitemap->showXml('<?xml version="...')
#4 [internal function]: app\controllers\SiteController->actionSitemap()
#5 /var/www/html/vendor/yiisoft/yii2/base/InlineAction.php(57): call_user_func_array(Array, Array)
#6 /var/www/html/vendor/yiisoft/yii2/base/Controller.php(178): yii\base\InlineAction->runWithParams(Array)
#7 /var/www/html/vendor/yiisoft/yii2/base/Module.php(552): yii\base\Controller->runAction('sitemap', Array)
#8 /var/www/html/vendor/yiisoft/yii2/web/Application.php(103): yii\base\Module->runAction('site/sitemap', Array)
#9 /var/www/html/vendor/yiisoft/yii2/base/Application.php(385): yii\web\Application->handleRequest(Object(app\components\LangRequest))
#10 /var/www/html/web/index.php(12): yii\base\Application->run()
#11 {main}