An error has happened during application run. See exception log for details.
Fatal error: Uncaught Exception: Warning: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: /var/lib/php/sessions) in /var/www/magento2/lib/internal/Magento/Framework/Session/SessionManager.php on line 136 in /var/www/magento2/lib/internal/Magento/Framework/App/ErrorHandler.php:61
Stack trace:
#0 [internal function]: Magento\Framework\App\ErrorHandler->handler(2, 'session_write_c...', '/var/www/magent...', 136, Array)
#1 /var/www/magento2/lib/internal/Magento/Framework/Session/SessionManager.php(136): session_write_close()
#2 [internal function]: Magento\Framework\Session\SessionManager->writeClose()
#3 {main}
thrown in /var/www/magento2/lib/internal/Magento/Framework/App/ErrorHandler.php on line 61