Fatal error: PHP notice in file /var/www/clients/client1/web1/web/portal/wcf/lib/system/session/CookieSessionFactory.class.php (121): Use of undefined constant COOKIE_PREFIX - assumed 'COOKIE_PREFIX'

Information:

error message: PHP notice in file /var/www/clients/client1/web1/web/portal/wcf/lib/system/session/CookieSessionFactory.class.php (121): Use of undefined constant COOKIE_PREFIX - assumed 'COOKIE_PREFIX'
error code: 0
file: /var/www/clients/client1/web1/web/portal/wcf/lib/system/WCF.class.php (255)
php version: 5.6.40-0+deb8u9
wcf version: 1.0.11 pl 4 (Horizon)
date: Wed, 08 Apr 2020 22:20:40 +0000
request: /portal/index.php?page=Thread&threadID=2469
referer:

Stacktrace:

#0 /var/www/clients/client1/web1/web/portal/wcf/lib/system/session/CookieSessionFactory.class.php(121): WCF::handleError(8, 'Use of undefine...', '/var/www/client...', 121, Array)
#1 /var/www/clients/client1/web1/web/portal/wcf/lib/system/session/SessionFactory.class.php(61): CookieSessionFactory->readSessionID()
#2 /var/www/clients/client1/web1/web/portal/lib/system/WBBCore.class.php(170): SessionFactory->get()
#3 /var/www/clients/client1/web1/web/portal/wcf/lib/system/WCF.class.php(91): WBBCore->initSession()
#4 /var/www/clients/client1/web1/web/portal/global.php(18): WCF->__construct()
#5 /var/www/clients/client1/web1/web/portal/index.php(7): require_once('/var/www/client...')
#6 {main}