Nextcloud offers CalDav Synchronizer for Outlook users

Thanks for your input!
I will give Akruto a chance and then switch to your solution if something goes wrong.

I’m having trouble with a self-signed certificate, which is supported according to the article.

When I go to test settings, it reads:

An error occurred while sending the request.
The underlying connection was closed: Could not establish trust relationship for SSL/TLS secure channel.
The remote certificate is invalid according to the validation procedure.

I generated a certificate with openssl according to this guide:

Is there a setting that I need to check?

Any help is appreciated.

1st sorry for my english,
2e Thank you this addon is very good !
3e For Mac user With outlook or mail can you make version for us ?

Best regards,

This actually works very well (for 1 person).

Warning for those trying to sync shared calendars from nextcloud to outlook, etc. I erased all of my appointments.

I have several people on our nextcloud instance share their calendar with me, but that doesn’t seem to import into Outlook easily.

I’m thinking I might have to create several distinct calendars in outlook, then manually setup profiles for each shared nextcloud calendar and map it to an outlook calendar.

Anybody try this with shared calendars? I’m just afraid to tell my users what to do in outlook and have them accidentally erase their calendars and have it replicate to the server. Could be bad.


Would love to use CalDav synchronizer on outlook but caldav sync makes ouitlook crash on startup! Had to disable calday sync to access outlook again.
Any idea where I can start investigation?

I like to share another Outlook add-in called EVO Collaborator for Outlook that works with Nextcloud. I think many Nextcloud users were migrating from ownCloud like my company. My company was using this Outlook add-in to sync with ownCloud before migration. Then, my boss asked me to consult EVO staff to see if they will support Nextcloud. EVO staff told me Nextcloud and ownCloud are basically the same on CalDAV and CardDAV infrastructure-wise. Thus, ECO is working on Nextcloud too. But a syntax for server URL must follow in format like this: https://nextcloud_server//remote.php/, Then, I tried it and it actually works.

I have the outlook app installed on my android phone. How do I add the calendar of NC?

The add-on works fine with outlook 2010 except for the free/tentative/busy status which doesn’t map to nextcloud.
When the status is set to free or tentative in either outlook or nextcloud and the event is edited on its counterpart, the status revert back to busy.

I’d like to use this add-on but the installation process requires administrator privileges (which I don’t have). Is there any option that could let me use CalDav Synchronize as a standard user ?


I came across the Outlook CalDav Synchronizer via the online Nextcloud Conference talks, very impressive work! I do understand the demand for a sync with Outlook, given it’s dominance on the Windows OS.
So here a possibly more fundamental question: I am wondering if the sync to (cloud-based) Outlook clients does not defy the rational of most Nextcloud users to have “calendars and contacts in a safe private cloud”? I am aware of options to encrypt the transfer and storage on some cloud solutions, are there any recommendations or validations for the peace-of-mind of users/admins from privacy-concerned (EU GDPR!) enterprises?


I like it, it worked on first try. But there is one thing I am missing and this is “sync this category only”.
I have my complete contact list on my Google account but only want to sync category “work” to Nextcloud and from there to Outlook. Is this in some way possible?


It is nice, but in Nextcloud 15 the presets for Nextcloud do not work anymore.
There is an error: DataAccess.WebDavClientException: Response status code does not indicate success: ‘415’ (‘Unsupported Media Type’).

With the default preset it works, but one can not choose a calendar.

I am working with Outlook 2007 and 2010 Clients using CalDav Synchronizer V 3.5, which should be the newest one right now. Nexcloud is running on the latest version also (15)…

We would like to sync both, contacts and calenders but we do have the following issues:

  • After first sync, for each contact, the birthday was synced into a separate calender. That’s fine, but it failed to sync the Date of the aniversary-field.
    It was not synced at all.
    I was expecting it to be either in an own calender “aniverseries” or into the birthday-calender.

  • We found, that some information, outlook stores on the “Details” tab (e.g. the name of the spouse oder the aniversary date) is not synced at all.
    Thats a problem, since we use to sync the contacts between the outlook-clients using nextcloud as a connecting server.
    So if my original entry contains a spouse, its synced to another client without it. If there is something changed and than synced back, the information may be lost on all clients…

So, not showing this information on the web frontend in nextcloud would not be our primary problem, as long, as the information is stored and synced correctly…



seems to be getting discussed closer here in the german part of the forum.
prolly no problem of caldav synchronizer.

Yes, I created that thread.
But thought, the topic maybe fits in here as well…

Right now, I am not shure, WHICH Part (nextcloud / caldav synchronizer / outlook) is causing the problem…

sure thing you created it. just wanted to let ppl know about the (german) crossposting… since sometimes it’s kinda difficult to keep track about everything.

Meanwhile, I found out, that even if I import a VCF 3 File containing the Informations about Spouse and anniversary, its ignored (or not shown) in nextcloud…

Most likely because custom fields are used instead of standardized fields :wink:

I am not shure, how CalDac Synchronizer works here.
If the software makes a vcard-File out of all the outlook-contacts, it should be able to include the fields in the right way.

Meanwhile I found the switch to include the anivarsary. So “only” the spouse is failing to be synced now…

Thank you for this great step-by-step-tutorial!

Unfortunately I don’t get any tasks from my Nextcloud instance displayed within Outlook, my calendars work fine. Can anyone help me here?

Thank in advance!