Can't first login to WAP after fresh install CentOS 7, Kolab 3.3

[Honza Burian]

Hi there,

I installed CentOS 7, made basic security configuration, then
installed Kolab 3.3 with no errors.
Then I made security setup for Kolab using this guide
http://docs.kolab.org/howtos/secure-kolab-server.html

Now I tried to make first login to kolab-webadmin using this guide:
http://docs.kolab.org/howtos/kolab-webadmin-create-user.html#howto-kolab-webadmin-create-user

But when I enter cn=Directory Manager and coresponding password then I
get error:
Internal system error!

# less /var/log/kolab-webadmin/errors
[10-Sep-2014 22:27:36 +0200](2b32v31rvpharkensitrp57qr4): PHP Error:
Login failed. Unable to decode response (POST)

# less /var/log/dirsrv/slapd-email/access
[10/Sep/2014:22:27:52 +0200] conn=420 fd=67 slot=67 connection from ::1 to ::1
[10/Sep/2014:22:27:52 +0200] conn=420 op=0 BIND dn="cn=Directory
Manager" method=128 version=3
[10/Sep/2014:22:27:52 +0200] conn=420 op=0 RESULT err=0 tag=97
nentries=0 etime=0 dn="cn=directory manager"
[10/Sep/2014:22:27:52 +0200] conn=420 op=1 SRCH
base="cn=kolab,cn=config" scope=2 filter="(&(associatedDomain=*))"
attrs="associatedDomain"
[10/Sep/2014:22:27:52 +0200] conn=420 op=1 RESULT err=0 tag=101
nentries=1 etime=0


Any ideas?
Thanks in advance for anything.

Best Regards
John