calendar http error 500
Hello, I just installed calendar and the page /? _ task = calendar has an error http 500. in the logs I find:
[15-Aug-2019 08:05:49 +0000]: <c3bdb7ed> PHP Error: Failed to load plugin file /usr/share/roundcubemail/plugins/libkolab/libkolab.php in /usr/share/roundcubemail/program/lib/Roundcube/rcube_plugin_api.php on line 173 (GET /webmail/?_task=calendar) [15-Aug-2019 08:05:49 UTC] PHP Fatal error: Uncaught Error: Class 'kolab_attachments_handler' not found in /usr/share/roundcubemail/plugins/calendar/lib/calendar_ui.php:102 Stack trace: #0 /usr/share/roundcubemail/plugins/calendar/calendar.php(308): calendar_ui->init_templates() #1 /usr/share/roundcubemail/program/lib/Roundcube/rcube_plugin_api.php(493): calendar->calendar_view() #2 /usr/share/roundcubemail/index.php(303): rcube_plugin_api->exec_action('calendar.index') #3 {main} thrown in /usr/share/roundcubemail/plugins/calendar/lib/calendar_ui.php on line 102
any suggestions to solve?
I installed the calendar on vestacp use centos 7.6 with php 7.3.8 Thank you