I really appritiate your help.
This is going to be more complicated for me. I tried installation steps in 2 other similar server and got exactly same problem. Reinstall plugin or roundcube was not helped, I tried to restore roundcubedb and one time I run the initial mysql of roundcube: mysql --user=da_admin --password="123456" da_roundcube < /roundcube/SQL/mysql.initial.sql
with no result.
Only when I removing 'calendar',
line from roundcube/config/config.inc.php and calendar disappears users can check mail.
What could be problem?