Cannot modify shared Nextcloud calendar in Thunderbird

[katkam]

The Basics

• Nextcloud Server version (e.g., 29.x.x):
  • 31.0.6
• Operating system and version (e.g., Ubuntu 24.04):
  • Ubuntu 24.04.2 LTS
• Installation method (e.g. AlO, NCP, Bare Metal/Archive, etc.)
  • Snap provided by Ubuntu. It currently runs on a local network
• Are you using CloudfIare, mod_security, or similar? (Yes / No)
  • No

Summary of the issue you are facing:

We are currently exploring Nextcloud features as a potential alternative to Microsoft. The calendar looks very promising feature-wise, so we try to integrate it to work with Thunderbird so people can share it with each other and modify each other’s calendars both in Nextcloud and Thunderbird. However, it currently works only one-way, with the users who created a calendar being able to modify it in Nextcloud, but people who received a link and added it to Thunderbird cannot. When one tries to modify it or add a new event in Thunderbird, a MODIFICATION_FAILED error shows up. What is also interesting is that when one adds the calendar to Thunderbird, it does not ask for Nextcloud account credentials, so this might also mean something.

What we tried is to simply share a link to the calendar with another user, include the user as “can edit” and then share. We did not specifically choose “copy subscription link”, assuming that sharing the normal link enables calendar editing.

The question: Is there a possibility to create a two-way modification of a calendar created in Nextcloud?

Steps to replicate it:

1. Create a calendar in Nextcloud
2. (Optional) Add the Nextcloud user with whom I want to share the calendar, with the same configured e-mail in Nextcloud and Thunderbird, and assign “can edit”
3. Copy the public link to the calendar
4. Add the calendar in Thunderbird via “New calendar → On the network → Location → Subscribe”

[scubamuc]

Hey @katkam welcome to the community ,

assuming you’re running locally without a valid SSL certificate or a self-signed certificate, you’ll run into issues, see How to configure Nextcloud snap

Self-signed certificate is easier to setup than Let’s Encrypt certificates, but will cause warnings in browsers and due to being very basic won’t work with some applications.

[katkam]

@scubamuc Thank you for the link! Could you please elaborate why having no SSL certificate hinders the performance of Nextcloud, considering it runs purely locally?

[scubamuc]

@katkam

considering it runs purely locally

Nextcloud was not designed to run locally, its a sharing service and expects TLS. The same goes for many apps connecting to Nextcloud… they expect to connect to an encrypted service. There are methods like running local DNS… but that requires a good deal of fiddling with certificates and FQDN etc. see 101: Split-Brain DNS (split-horizon) - #2 by tflidd and relevant topics Topics tagged splitbraindns.

[kesselb]

Thanks for reaching out.

I think it should work to share a calendar with “Edit” permission to another user, and than that user will be able to also modify the calendar. Keep in mind, that for the other user you need to use a different calendar url.

Tip: You find the right uri to be used in the calendar app.