Sorry to hear you’re facing problems. 
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If you’re using Nextcloud in a business/critical setting, paid and SLA-based support services can be accessed via portal.nextcloud.com where Nextcloud engineers can help ensure your business keeps running smoothly.
Getting help
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- Official documentation (searchable and regularly updated)
- How to topics and FAQs
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Some or all of the below information will be requested if it isn’t supplied; for fastest response please provide as much as you can. 
The Basics
- Nextcloud Server version (e.g., 29.x.x):
34.0.1
- Operating system and version (e.g., Ubuntu 24.04):
- Ubuntu 26.04
- Web server and version (e.g, Apache 2.4.25):
Nginx
- Reverse proxy and version _(e.g. nginx 1.27.2)
Nginx and Zabbix-Proxy
- PHP version (e.g, 8.3):
8.3
- Is this the first time you’ve seen this error? (Yes / No):
Yes
- When did this problem seem to first start?
Synchronizing the callendar in Caldav Synchronizer witch Outlook
- Installation method (e.g. AlO, NCP, Bare Metal/Archive, etc.)
Virtual Machine in Ubuntu Server 26 and Docker
- Are you using CloudfIare, mod_security, or similar? (Yes / No)
NO
Summary of the issue you are facing:
CaldavSynchronize synchronization does not work after changing the AD user’s password on the server.
Steps to replicate it (hint: details matter!):
-
Enable LDAP synchronization with AD in Nextcloud to authenticate logins to Nextcloud.
-
Set up a static app password.
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Synchronize your calendar using the CalDAV Synchronizer in Outlook with your LDAP login and app password.
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Change the user’s password on the AD server.
-
Calendar synchronization in CalDAV Synchronizer generates a user authorization error despite the configuration of a static app password.
-
The solution to this problem is to log in to Nextcloud via the Web UI. You do not need to change anything in the configuration or passwords. Everything works correctly until the next password change—whether it’s a forced reset or the standard one every 30 days.
It seems as though Nextcloud isn’t tracking changes between AD and LDAP in Nextcloud in real time. It only refreshes this information after a user logs in to the WebUI. All you need to do is log in; no other actions are required.
I’ve already changed the LDAP synchronization interval from 600 seconds to 0 seconds so that it constantly queries the AD server for the account’s password status.
Has anyone else encountered this problem and managed to resolve it?