Fatal error: PHP notice in file /var/www/clients/client1/web1/web/portal/wcf/lib/system/auth/UserAuthDefault.class.php (56): 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/auth/UserAuthDefault.class.php (56): 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+deb8u11
wcf version: 1.0.11 pl 4 (Horizon)
date: Fri, 10 Jul 2020 11:49:37 +0000
request: /portal/index.php?page=Thread&threadID=2552&s=3292d4643068c3846203b970a11c7968714da7c9
referer:

Stacktrace:

#0 /var/www/clients/client1/web1/web/portal/wcf/lib/system/auth/UserAuthDefault.class.php(56): WCF::handleError(8, 'Use of undefine...', '/var/www/client...', 56, Array)
#1 /var/www/clients/client1/web1/web/portal/wcf/lib/system/session/CookieSessionFactory.class.php(34): UserAuthDefault->loginAutomatically(true, 'WBBUserSession')
#2 /var/www/clients/client1/web1/web/portal/wcf/lib/system/session/SessionFactory.class.php(71): CookieSessionFactory->create()
#3 /var/www/clients/client1/web1/web/portal/lib/system/WBBCore.class.php(170): SessionFactory->get()
#4 /var/www/clients/client1/web1/web/portal/wcf/lib/system/WCF.class.php(91): WBBCore->initSession()
#5 /var/www/clients/client1/web1/web/portal/global.php(18): WCF->__construct()
#6 /var/www/clients/client1/web1/web/portal/index.php(7): require_once('/var/www/client...')
#7 {main}