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:
Nextcloud 33.0.0
- Operating system and version:
#1 SMP PREEMPT Debian 1:6.12.62-1+rpt1~bookworm (2026-01-19)
- Web server and version:
Server version: Apache/2.4.66 (Debian)
- Reverse proxy and version:
nginx version: openresty/1.27.1.2
- PHP version:
PHP 8.4.18 (cli) (built: Feb 24 2026 19:12:53) (NTS)
- Is this the first time you’ve seen this error? (Yes / No):
yes
- When did this problem seem to first start?
prob direct after installation
- Installation method (e.g. AlO, NCP, Bare Metal/Archive, etc.)
OMV Container
- Are you using CloudfIare, mod_security, or similar? (Yes / No)
nope
Summary of the issues you are facing:
collabora server check responses with 400 Badrequest.
The URL https://collab.kingma.ch returns OK the URL htps://collab.kingma.ch/ returns:
{"convert-to":{"available":false},"hasDocumentSigningSupport":true,"hasMobileSupport":true,"hasProxyPrefix":false,"hasSettingIframeSupport":true,"hasTemplateSaveAs":false,"hasTemplateSource":true,"hasWASMSupport":false,"hasWopiAccessCheck":true,"hasZoteroSupport":true,"productKitVersion":"25.04.9.2","productKitVersionHash":"3aa0ebc4","productName":"Collabora Online Development Edition","productVersion":"25.04.9.2","productVersionHash":"a9b866688f","serverId":"b281a422"}
or
| convert-to | |
| available | false |
| hasDocumentSigningSupport | true |
| hasMobileSupport | true |
| hasProxyPrefix | false |
| hasSettingIframeSupport | true |
| hasTemplateSaveAs | false |
| hasTemplateSource | true |
| hasWASMSupport | false |
| hasWopiAccessCheck | true |
| hasZoteroSupport | true |
| productKitVersion | 25.04.9.2 |
| productKitVersionHash | 3aa0ebc4 |
| productName | Collabora Online Development Edition |
| productVersion | 25.04.9.2 |
| productVersionHash | a9b866688f |
| serverId | b281a422 |
Steps to replicate it (hint: details matter!):
-
Open Nextcloud administration
-
Go to ONLYOFFICE
-
Enter htps://collab.kingma.ch and click Save
A toast appears:
Error when trying to connect (Client error: GET https://collab.kingma.ch/healthcheck` resulted in a 400 Bad Request response)`
and indeed attempts to open https://collab.kingma.ch/healthcheck does end in 400 Bad Request. But the server seems helty.
Log entries
None
Nextcloud
PASTE HERE
Web Browser
Apps
Enabled:
- activity: 6.0.0-dev.0
- admin_audit: 1.23.0
- bookmarks: 16.1.3
- brewmemo: 0.6.0
- bruteforcesettings: 6.0.0-dev.0
- calendar: 6.2.1
- circles: 33.0.0
- cloud_federation_api: 1.17.0
- comments: 1.23.0
- contacts: 8.4.1
- contactsinteraction: 1.14.1
- cookbook: 0.11.6
- dashboard: 7.13.0
- dav: 1.36.0
- encryption: 2.21.0
- end_to_end_encryption: 2.0.0
- federatedfilesharing: 1.23.0
- federation: 1.23.0
- files: 2.5.0
- files_downloadlimit: 5.1.0-dev.0
- files_external: 1.25.1
- files_pdfviewer: 6.0.0-dev.0
- files_reminders: 1.6.0
- files_sharing: 1.25.2
- files_trashbin: 1.23.0
- files_versions: 1.26.0
- firstrunwizard: 6.0.0-dev.0
- fulltextsearch: 33.0.0
- groupfolders: 21.0.6
- logreader: 6.0.0
- lookup_server_connector: 1.21.0
- nextcloud_announcements: 5.0.0
- notes: 4.13.0
- notifications: 6.0.0
- oauth2: 1.21.0
- onlyoffice: 10.0.0
- password_policy: 5.0.0-dev.0
- photos: 6.0.0-dev.0
- privacy: 5.0.0-dev.0
- profile: 1.2.0
- provisioning_api: 1.23.0
- recommendations: 6.0.0-dev.0
- related_resources: 4.0.0-dev.0
- richdocuments: 10.1.0
- serverinfo: 5.0.0-dev.0
- settings: 1.16.0
- sharebymail: 1.23.0
- support: 5.0.0
- survey_client: 5.0.0-dev.0
- suspicious_login: 11.0.0-dev.0
- systemtags: 1.23.0
- text: 7.0.0-dev.3
- theming: 2.8.0
- twofactor_backupcodes: 1.22.0
- twofactor_nextcloud_notification: 7.0.0
- twofactor_totp: 15.0.0-dev.0
- updatenotification: 1.23.0
- user_status: 1.13.0
- viewer: 6.0.0-dev.0
- weather_status: 1.13.0
- webhook_listeners: 1.5.0
- workflowengine: 2.15.0
Disabled:- app_api: 33.0.0 (installed 32.0.0)
- camerarawpreviews: 0.8.8 (installed 0.8.8)
- documentserver_community: 0.2.1 (installed 0.2.1)
- keeweb: 0.6.22 (installed 0.6.22)
- user_ldap: 1.24.0 (installed 1.22.0)