email in Outlook 2016 stay in send queue (only CC and BCC reipients)

  • Hi,

    according to fbartels post in the UCS forum i ask my question here in the kopano forum. On the UCS - Kopano Server i have the following issue:

    • When i write a e-mail only to CC and BCC recipients with Outlook 2016 the mail will be send multiple times. When i delete the mail in the Outlook ‘Postausgang’ the transfer is stopped. So i think Outlook don’t recognize that the e-mail was send to kopano and trie to send it again. This happened last week for the fist time and yesterday again but not every time when sending e-mails to CC and BCC recipients.

    Here are the version infomations of the server:

    ii  kopano-server-packages                                                                           all          Metapackage to install the entire Kopano Core stack
    ii  kopano-webapp                                                                                  all          New and improved WebApp for Kopano
    ii  kopano-webapp-plugin-desktopnotifications                                                        all          Kopano WebApp Desktop notifications plugin
    ii  kopano-webapp-plugin-filepreviewer                                                               all          Kopano File previewer plugin
    ii  kopano-webapp-plugin-files                                                                     all          Adds Files functionality to Kopano enabling access to WebDAV and other files backends.
    ii  kopano-webapp-plugin-filesbackend-owncloud                                                       all          Adds Owncloud specific functionality to Kopano Files plugin.
    ii  kopano-webapp-plugin-filesbackend-smb                                                            all          Adds Samba specific functionality to Kopano Files plugin.
    ii  kopano-webapp-plugin-folderwidgets                                                             all          Kopano WebApp folder widgets plugin
    ii  kopano-webapp-plugin-mdm                                                                        all          Kopano WebApp MDM plugin
    ii  kopano-webapp-plugin-smime                                                                      all          Kopano WebApp S/MIME plugin
    ii  kopano-webapp-plugin-spell                                                                       all          Kopano WebApp Spellchecker plugin
    ii  kopano-webapp-plugin-spell-de-de                                                                  all          Kopano WebApp Spellchecker German dictionary plugin
    ii  kopano-webapp-plugin-spell-en                                                                     all          Kopano WebApp Spellchecker English dictionary plugin
    ii  kopano-webapp-plugin-spell-nl                                                                     all          Kopano WebApp Spellchecker Dutch dictionary plugin
    ii  kopano-webapp-plugin-titlecounter                                                              all          Kopano WebApp Titlecounter plugin
    ii  kopano-webapp-plugin-webappmanual                                                              all          Kopano WebApp Manual plugin
    ii  kopano4ucs                                          1.6.2                                                               all          Kopano4ucs integration package for Univention Corporate Server
    ii  kopano4ucs-app                                      1.6.2                                                               all          Package for UCS app specific logic
    ii  kopano4ucs-lib                                      1.6.2                                                               all          Library package for common Kopano4ucs functions
    ii  kopano4ucs-schema                                   1.6.2                                                               all          LDAP schema for the Kopano4ucs integration
    ii  kopano4ucs-udm                                      1.6.2                                                               all          UDM extensions for the Kopano4ucs integration
    ii  kopano4ucs-webapp                                   1.5.33                                                              all          Kopano4ucs kopano-webapp integration package for Univention Corporate Server
    ii  kopano4ucs-z-push                                   1.5.33                                                              all          Meta package for Z-Push installation
    ii  z-push-kopano                                       2.4.5+0-0                                                           all          Z-Push for Kopano
    ii  z-push-kopano-gabsync                               2.4.5+0-0                      
    UCS: 4.4-3 errata455
    Installed: bareos=18.2.7 cups=2.2.1 fetchmail=6.3.26 kde=5.8 kopano-core= kopano-webapp= nagios=4.3 samba4=4.10 z-push-kopano=2.4.5

    In the z-push log i can’t find any unsusual entries.

    Is there any place to find further informations?

    Kind regards


  • Kopano

    Hi @Jochen77,

    so outlook is indeed connected over ActiveSync? Even if you don’t think its unusual it could help to see the z-push logging (possibly wbxml) of that user when Outlook submits the message.

    Your post in just mentioned that this happens when there are recipients in cc, here you say it happens when the only recipients are in cc/bcc. So its the latter?

    Do you see a difference in recipients for the cases where you can reproduce to where to can’t?

  • Hi,

    it happended yesterday for the second time. There were only recipients in cc an bcc. Last week i’m not sure about but i think last week there were only BCC recipients.

    Yes, Outlook is connected als exchange active sync client.

    I checked the z-push log in /var/log/z-push. In the z-push.log i can see the client IP logging at this time and in the z-push-error.log there is no entry at this timestamp. Is there any further log-file?

    Because it happened 2 times now i’m not sure how to reproduce the behavior. In both cases there were many recipients some external and some accounts on the server itself.

    Kind regards Jochen

  • Kopano

    Unfortunately I am unable to reproduce the issue.

    I have tested this with Outlook ProPlus 2016 (the 2019 Outlook is virtually identical as far as I know) and our own production system which at the time of writing is on 8.7.9.

    I have opened a new mail in Outlook, added two recipients in the bcc, filled the subject and sent the message. No recipients were added in to or cc.

    The mail was only sent and received once.

    @Jochen77 said in email in Outlook 2016 stay in send queue (only CC and BCC reipients):

    I checked the z-push log in /var/log/z-push. In the z-push.log i can see the client IP logging at this time and in the z-push-error.log there is no entry at this timestamp. Is there any further log-file?

    For z-push you can enable wbxml logging. this will log whatever is transmitted over the line. You can find instructions for this at

    I do remember something with “BCC only” from a while back, but don’t remember what exactly it was. Maybe only WebApp did not like it if you don’t have an explicit recipient.

  • Kopano

    Hi @Jochen77,

    First I suggest to update Z-Push to a more recent version (currently 2.5.1, 2.5.2 final planned to release in two weeks). There’s no development or bugfixes for Z-Push 2.4.X anymore.

    It would help if you would post WBXML level Z-Push log excerpt for such SendMail request.

    Are you using KOE? If yes, did you check KOE log for errors?

    Finally, did you check Windows Events Viewer for Outlook errors?


  • O.K. the next step is to activate the wbxml logging. As i read the logfile is very large so i will do this the next time when a e-mail to CC and BCC recipients will be send.

    @fbartels: I’m not able to repoduce this issue every time. May only be a problem with many recipients (more than 10 or 15).

    @Manfred: I will check the Windows Event Viewer for Outlook errors and come back when done.



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