Kolab 3.4 on debian 8: multidomain problem -> cannot add users

[Michael Stuber]

Hi

Single domain setup is working so far.

I followed the steps from:
https://docs.kolab.org/howtos/multi-domain.html

Adding a new domain using the Web Administration Panel ends up in a
pop-up with the error message "Server Error". The domain ist created but
I cannot add any users (fields are grayed out).

ldapsearch -x -H ldap://localhost -b "cn=kolab,cn=config" -D
"cn=Directory Manager" -w "XXX" ->

# extended LDIF
#
# LDAPv3
# base <cn=kolab,cn=config> with scope subtree
# filter: (objectclass=*)
# requesting: ALL
#

# kolab, config
dn: cn=kolab,cn=config
objectClass: top
objectClass: extensibleobject
cn: kolab

# newdomain.ch, kolab, config
dn: associateddomain=newdomain.ch,cn=kolab,cn=config
associatedDomain: newdomain.ch
objectClass: top
objectClass: domainrelatedobject
objectClass: inetdomain

# olddomain.ch, kolab, config
dn: associateddomain=olddomain.ch,cn=kolab,cn=config
objectClass: top
objectClass: domainrelatedobject
objectClass: inetdomain
associatedDomain: olddomain.ch
associatedDomain: localhost
associatedDomain: localhost.localhost

# search result
search: 2
result: 0 Success

# numResponses: 4
# numEntries: 3

Any hints?
Kind regards Michael