tail -f /usr/local/cwpsrv/var/services/roundcube/logs/errors.log
PHP Fatal error: Uncaught Error: Class ‘Spoofchecker’ not found in /usr/local/cwpsrv/var/services/roundcube/program/lib/Roundcube/rcube_spoofchecker.php:50
Solution:
nano /usr/local/cwpsrv/var/services/roundcube/program/lib/Roundcube/rcube_spoofchecker.php
before line:
// Spoofchecker is part of ext-intl (requires ICU >= 4.2)
$checker = new Spoofchecker();
insert:
return false;