Ldap initialization ... failed. (28416)

I am trying to setup Zimbra on my Linode (ubuntu). It has been for over 12 continuous hours, but I am unable to set it up correctly. I already followed the guides from the internet too much. For the last try I tried this: Configure Zimbra and as usual the same error occured. This is mistake:

Installing Proxy SSL certificate...done.
Initializing ldap...failed. (28416)


ERROR



Configuration failed

Please address the error and re-run /opt/zimbra/libexec/zmsetup.pl to
complete the configuration.

Errors have been logged to /tmp/zmsetup05102015-071817.log

      

        
        
        
      

    

And these are the last few lines of the log file:

Sun May 10 07:22:20 2015 done.
Sun May 10 07:22:20 2015 Installing LDAP SSL certificate...
Sun May 10 07:22:20 2015 *** Running as root user: /opt/zimbra/bin/zmcertmgr deploycrt self
** Saving server config key zimbraSSLCertificate...failed.
** Saving server config key zimbraSSLPrivateKey...failed.
** Installing mta certificate and key...done.
** Installing slapd certificate and key...done.
** Installing proxy certificate and key...done.
** Creating pkcs12 file /opt/zimbra/ssl/zimbra/jetty.pkcs12...done.
** Creating keystore file /opt/zimbra/mailboxd/etc/keystore...done.
** Installing CA to /opt/zimbra/conf/ca...done.
Sun May 10 07:22:25 2015 done.
Sun May 10 07:22:25 2015 Installing Proxy SSL certificate...
Sun May 10 07:22:25 2015 *** Running as root user: /opt/zimbra/bin/zmcertmgr deploycrt self
** Saving server config key zimbraSSLCertificate...failed.
** Saving server config key zimbraSSLPrivateKey...failed.
** Installing mta certificate and key...done.
** Installing slapd certificate and key...done.
** Installing proxy certificate and key...done.
** Creating pkcs12 file /opt/zimbra/ssl/zimbra/jetty.pkcs12...done.
** Creating keystore file /opt/zimbra/mailboxd/etc/keystore...done.
** Installing CA to /opt/zimbra/conf/ca...done.
Sun May 10 07:22:30 2015 done.
Sun May 10 07:22:30 2015 checking isEnabled zimbra-ldap
Sun May 10 07:22:30 2015 zimbra-ldap is enabled
Sun May 10 07:22:30 2015 Initializing ldap...
Sun May 10 07:22:30 2015 *** Running as zimbra user: /opt/zimbra/libexec/zmldapinit
Connection refused at /opt/zimbra/libexec/zmldapinit line 138.
Sun May 10 07:23:13 2015 failed. (28416)
Sun May 10 07:23:13 2015

ERROR

      

        
        
        
      

    

I'm not sure what might be wrong or how to fix it. If any of you have ever faced such a problem and know the solution, please let me know.

thank