Hello,
OK
same bug
Object exists: cn=kopanoDisabledFeature,cn=kopano,cn=custom attributes,cn=univention,dc=thhoe,dc=de
LDAP Error: Undefined attribute type: kopanoMrAcceptRecurring: attribute type undefined
__JOINERR__:FAILED: /usr/lib/univention-install/70kopano4ucs.inst
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* Join failed! *
* Contact your system administrator *
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* Message: Please visit https://help.univention.com/t/8842 for common problems during the join and how to fix them -- FAILED: 70kopano4ucs.inst
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Thu Nov 22 14:37:03 CET 2018: finish /usr/sbin/univention-join