No kopano store is created for new users
This Problem occurs in an older UCS Version, so maybe the solution is outdated by now.
Search for these lines in the CFG
# scripts which create stores for users from an external source # used for ldap and unix plugins only createuser_script = /etc/kopano/userscripts/createuser deleteuser_script = /etc/kopano/userscripts/deleteuser creategroup_script = /etc/kopano/userscripts/creategroup deletegroup_script = /etc/kopano/userscripts/deletegroup createcompany_script = /etc/kopano/userscripts/createcompany deletecompany_script = /etc/kopano/userscripts/deletecompany
Comment them all out. Then the defaults, which refer to
/usr/lib/kopano/userscripts/, take effect.