Kopano multi domain/tenant


I would like to host multiple domain for my mail service. I am using kopano as mail server. Does Kopano support such scenario ? I added multiple domains under Domain > mail and define different mail accounts as Kopano user but it didnt work. Since my first domain works correctly i am curious if kopano dont support such scenario on UCS.



Hi @Talion,

multiple mail domains should be no problem. As you did you have to add them to the mail domains in the UCS ui and from there on you will be able to add addresses from that domain to either the primary address of a user or as an alias. If that did not work for you then I am interested in learning which error messages you’ve gotten along the way.

What does not work out of the box is the multi tenant functionality of Kopano. This is kept out of the app to not encourage people from offering hosting services on top of the free app included in UCS, but can be added with a bit of knowledge about UCS/Kopano and a few extended attributes. The Kopano Prof. Services department can help you get started with this.

Hello @fbartels,

Thank you for replying to my post.

When i sent an email to my newly added domain from gmail. I am getting this error.

550 5.1.1 user@domain.com: Recipient address rejected: User unknown in virtual mailbox table

But i can able to send email to gmail without any problem.

I added a new user with user@domain.com as primary email.



Did you also add the mail domain (domain.com) in the GUI?

Afaik he has to, else one would not be able to specify an address belonging to that domain, at least that would be the default behaviour.

I am rather wondering if the message is coming from the UCS system or if maybe the mx records are still pointing to another server.

Yes, i did already add my domain to UCS > Domain > Mail.


Sorry for late replay.

@fbartels after your comment i double check DNS and yes you are right there were mx record that i oversee earlier. I now cleanup my dns and i dont receive 5.1.1 but i dont recieve the email on kopano webapp either. After i logged my first account which is lets say domain1.com i see that all the mails that i sent to domain2.com si there! Please advise.


My usersname in this format;



Thats hard to do with the current amount of information. I would recommend to open a ticket with the Kopano support so that someone can have a direct look at your system. More information are at https://kopano.com/pricing/support-professional-services/

@fbartels What other informations do you need ? I can supply it here so other people who may have same problems can learn.


You don’t want that others can help themselves, you want something for free for yourself :wink:

But ok, lets start with:

  • what version of Kopano and Univention are you using?
  • where is it installed?
  • what are the actual usernames/email addresses?
  • what is logged in mail.log at the time of delivery?

Since Kopano only cares about the existence of a primary email address (and not to which domain it belongs) I would guess that you have some aliases defined for your “domain1” which leads to them being delivered into this mailbox and not the mailbox of “domain2”.

@fbartels Dont you think this is a bit absurd/weird comment for a company (Kopano) who leech all the benefits of open source (free) tools to make money ? :wink: You destroy all the fundementals of opensource with one sentence, congratulations :slight_smile:

I dont need your help or someone in your mind, thanks anyway.

Good night.


@Talion i wish you good luck!